Known limits

These limits hold in version 1.4.0. The FINDING numbers in parentheses name the tests in the repository that reproduce or check each case, except FINDING-031, FINDING-033, FINDING-127, FINDING-128, FINDING-151, FINDING-163, FINDING-165 and FINDING-176, which no test names. For FINDING-177, only the Android case is tested, and that case is fixed.

Files and links

• A rename made in Cairn refuses a name that differs only in case from another file or folder in the same folder, as creating does. Files made or renamed outside Cairn, and new or renamed files that sync brings from another device, skip this check, so on Linux and in Android app storage a notebook can hold two notes whose names differ only in case. A macOS or Windows device then gives one of them a conflict copy name, and an Android shared folder keeps one and lists the other under "Files not synced" (FINDING-053).
• By design, names with a backslash do not sync. The app lists them under "Files not synced" with "The name contains a backslash. Rename it to sync it." A synced note renamed outside Cairn to such a name counts as deleted, so the other devices move it to their trash (FINDING-011).
• When the plain file of a Unicode twin goes, the twin takes the plain name at the next full rescan, and the other devices get it under that name through sync (FINDING-011).
• A file reached under two names through symlinks (a link to a folder of the notebook, two links to one folder, or a symlink to a note) syncs under one name. Version 1.1.0 and older synced it under both, so other devices may have a second copy. That copy is no longer updated, with two exceptions: deleting the note on the device with the link deletes the copy too, unless another device changed the copy meanwhile, and when another device deletes the note's own copy and keeps the second one, the second one syncs in its place. An edit or rename of the second copy waits on the device with the link and is listed under "Files not synced". A device that still runs 1.1.0 or older with the link moves the real note to the trash when another device deletes either copy (for a symlink to a note, the note's own copy), and its next sync deletes the other copy on every device, so every such device must be updated first. Two devices whose links differ for the same files can sync different names of one file; each then holds and lists the other's changes. While a folder that holds the link cannot be read, a delete of the note's own copy from another device waits, and a new file with the content of a note in that folder is not uploaded; both are listed. After a restart in that state, an edit made through the other name meanwhile can sync as a second copy. After the sync state is rebuilt, an older copy that differs from the note waits, listed, and so does a delete of the note from another device (FINDING-224).
• A remote move of a synced symlink to a file into another folder waits, listed, when the link's target is a relative path, because the move can break the link. Cairn does not check whether it would. This holds for any such link, not only one that gives a note a second name (FINDING-224).
• A rename or move made in Cairn refuses a Windows device name (CON, PRN, AUX, NUL, COM0 to COM9 and LPT0 to LPT9, also with ¹, ² or ³, CONIN$ and CONOUT$, with any extension) on every platform. Renames that sync applies still take such a name, except on Windows, where sync lists the file under "Files not synced". So a note such as con.md that was made outside Cairn or came from another device cannot be moved to another folder in Cairn under that name; rename it first.
• Files with #, |, [ or ] in their names are left out of the [[ autocomplete, because no wikilink can name them. Offering them there as Markdown links is deferred. Of two files whose names differ only in case, only the one that wikilinks lead to is offered (FINDING-184).
• Cairn does not save settings, snippets or a font file through a .cairn, .cairn/snippets or .cairn/fonts folder that is a link out of the notebook, and does not move a font file to the trash through one: it shows an error and writes nothing outside the notebook. Reads still follow such links, .cairn/plugins and .cairn/fonts included, so plugin code and the font file can come from outside the notebook, though a plugin still needs the user's approval (FINDING-013). Cairn refuses the settings, a snippet or a plugin in .cairn/ that is larger than 16 MB, and a plugin file that large can keep Settings, then Plugins, from listing any plugin. If the notebook's settings turn it on, it can also keep other plugins from starting.
• A hard-linked note is written in place after a temp copy. A crash during that write can leave the note half written under all its names, with the full text in a .cairn-tmp-* file next to it. If the write fails, Cairn renames the copy over the note, so the link splits and the other names can be left half written (FINDING-013). On Windows, a save always splits the link (see Windows, below).
• Images in dot-folders do not show, in a note or in an image tab, and the tree, the quick switcher and search do not list them (FINDING-022).
• Image tabs are not reopened when Cairn starts again. Versions 1.0.0 and 1.1.0 open every tab of the saved session that is not the graph as a note, so the session keeps the format they read, and they still restore the other tabs from it.
• Search lists images by their path only, and a query with a tag or a quoted phrase lists none.
• An external edit that keeps the size and mtime (rsync -t, cp -p, coarse FAT or SMB timestamps) is not picked up until the file changes again; a save from an open tab still compares the content (FINDING-046).
• An external save that lands between Cairn's last check and its rename can be overwritten. In testing, none of 500 saves at a 50 ms cadence were overwritten, and about 2% were in a back-to-back stress test. This window is accepted as a known limit (FINDING-047).
• On desktop, a save cut off by a crash leaves a .cairn-tmp-* file next to the note. Cairn does not list it, and on Linux it is hidden, but on Windows a leading dot does not hide a file, so File Explorer shows it (FINDING-177).
• Renaming a note does not rewrite the links that point to it.

Sync

• The server stores each device's name in plaintext. Encrypting it is later work (FINDING-152).
• In Settings, then Sync, emptying "This device's name" fills it again at once with the name that Cairn suggests. To change the name, select it and type the new one.
• A remote change this device cannot apply (a name its file system refuses, a folder it cannot read or write) stays pending and is listed under "Files not synced", and that file's local changes wait with it. On Windows this holds for a name with <, >, :, ", |, ? or *, a name that ends in a dot or a space, and a device name such as con.md, which other systems allow; such a file is listed with "Windows does not allow the name". A file on one device and a folder of the same name on another wait until one side renames (FINDING-017, FINDING-057).
• Files over about 150 MB do not sync. The app lists them under "Files not synced" and does not read them for upload. A larger record already on a server stops every pull. A pull holds about one 64 MB batch of changes plus one page of up to 200 MB in memory, and each sync reads every pending change into memory when it starts. When the sync state is rebuilt, which includes the first sync of a notebook folder that already has files, the changes beyond the first batch are downloaded twice in that sync (FINDING-016, FINDING-019).
• Deleting every file in the notebook on purpose syncs only once the notebook has a file again. Every file counts, not only notes, but files in hidden folders do not, so when images or other files stay, deleting every note syncs at once (FINDING-006).
• A reset server is noticed only while it has fewer changes than the device has seen (FINDING-058).
• After the sync state is rebuilt (lost or damaged, or sync turned off and on), notes deleted elsewhere come back, because sync makes no automatic deletes (FINDING-054).
• When sync writes a remote change or moves a file to the trash, a file that another program writes in the few milliseconds after Cairn's last check is not protected (FINDING-015).
• On Windows and in Android shared folders, sync misses an edit made outside Cairn that keeps a note's size and puts back a modification time more than 3 s old (cp -p, rsync -t, a backup restore). It also misses another file of the same size and modification time moved over a note: the other devices keep the note's old text, and if that file had already synced elsewhere in the notebook, they move it to their trash. The new text is uploaded when the note changes again, and if another device edits the note first, the two versions are merged (FINDING-055).
• Downloaded files get the time of the download as their modification time, so the quick switcher's recent order on other devices follows the sync (FINDING-150).
• An empty note renamed outside Cairn syncs as a delete and a create, and so do identical notes renamed outside Cairn before one sync when two or more of them keep neither their file names nor their folders. Other devices move the old copies to their trash, and nothing is lost (FINDING-136).
• A note renamed outside Cairn and edited before the next sync syncs as a delete and a new note, because sync does not match notes by similarity. Its version history starts again, other devices move the old note to their trash, and an edit made elsewhere in the meantime comes back under the old name. A rename made in Cairn while sync is set up keeps the history (FINDING-062).
• Restoring a version needs a connection (FINDING-024). The version history of a note renamed and edited in Cairn shows only after the next sync, about 4 s later (FINDING-165).
• A note deleted on one device inside a folder that another device renamed comes back in the renamed folder, whichever device syncs first. A rename that sync makes itself (to a conflict copy name) also beats a delete once it is uploaded, so a note deleted on one device can come back under a conflict copy name (FINDING-148).
• When the kept one of two identical copies is both renamed and edited before a device that holds the deleted copy syncs, or is edited or renamed in the moment between another device's check and its delete, that device moves its own copy to its trash. The kept note stays, so nothing is lost (FINDING-063).
• Sync finds names that differ only in case with Unicode lowercase, so names that a file system folds another way (such as ſ and s) are not caught. In a Linux folder with case folding turned on, a case-only rename from another device is pushed back to the old name. Nothing is lost (FINDING-004).
• Sync setup asks before it creates a notebook the server does not have. Notebook names on the server are case-sensitive, so "Notes" and "notes" are two notebooks (FINDING-083, FINDING-164). The server cannot delete a notebook, so a notebook made by a setup that was then cancelled stays there (FINDING-163).
• A reverse proxy must not reuse idle connections to the server for more than 10 s; the bundled Caddyfile uses 5 s. A client that keeps opening new half-sent connections can still use up the server's file descriptors. Without a valid token, the server closes each one after at most 10 s. With a valid token, a request body that stops arriving is cut off after 30 s, but one that keeps sending a little at a time is not (FINDING-076).
• Sync does not copy files or folders whose names start with a dot, such as the .cairn/ folder (settings, CSS snippets, plugins and the font file), and it does not copy empty folders. Moving a note into such a folder, for example .archive/, works like deleting it on your other devices: it goes to their trash.
• The server cannot read notes or make up their content, but it can hold back changes, send an older version of a note as the newest one, or mark a note as deleted, so that each device that has not changed the note moves it to its trash. It can also change the device name and the time that version history shows. Cairn notices none of this, except a server that has fewer changes than the device has seen (FINDING-058).
• The notebook key is stored unencrypted in the app's data folder on each device.

Windows

Version 1.3.0 has been tried by hand on Windows 11, on a 1920 by 1080 screen at 125% scaling. A second test by hand, with WebView2 154, tried the fixes that came from that test, except on a phone. Three changes came after it and are checked by tests only: the size check for items too large for the Recycle Bin, the error when Windows still deletes an item for good, and the spelling suggestions in the right-click menu. The items below say what still holds after those fixes, and what the second test found. The last item lists what nobody has tried yet.

• The installer is not signed, so Windows SmartScreen warns before it runs, and on a PC with Smart App Control turned on, Windows can block the installer and Cairn outright.
• If the folder Cairn was installed in is gone while Windows still lists Cairn as installed, the installer shows "Unable to uninstall!" and goes back to the same page. Choose "Do not uninstall" on that page, or run the installer with /S.
• Cairn does not remember the size and position of its window. It opens centered on the primary monitor, and smaller when its usual size would not fit in the area that the taskbar leaves free. The status bar is then in full view, but the window's bottom border, 1 pixel high, lies under the top edge of the taskbar.
• Where the Recycle Bin cannot take a file or folder, deleting it moves it to the notebook's .trash folder, without a question. This holds for a notebook on a network share or a mapped drive, on a USB stick or another drive without a Recycle Bin, or on a drive set to remove files at once ("Don't move files to the Recycle Bin"). It also holds for an item larger than the Recycle Bin of its drive takes: Cairn reads that size from the Recycle Bin's settings, or works out the size Windows gives it by default, and takes that size a little smaller, so an item close to it goes to .trash too. So does an item when Cairn cannot read its size or the Recycle Bin's. It holds for a delete made in Cairn, a delete that sync applies and the removal of the font file. Cairn's file tree does not show .trash, but File Explorer does. The Delete dialog still asks whether to move the item to the trash. If Windows still deletes an item for good instead of moving it to the Recycle Bin, Cairn says so: the delete fails with an error such as "video.mp4" was deleted for good: the Recycle Bin could not take it. A delete that sync applies then lists the file under "Files not synced" with that error, until the next sync. A note behind a folder link to a share, or to another drive whose Recycle Bin cannot take it, cannot be deleted in Cairn: the delete fails with an error and the note stays.
• A file or folder whose name ends in a dot or a space, or is a device name such as CON, can still be in the notebook if another program made it. Deleting it, or anything inside a folder with such a name, also moves it to the notebook's .trash folder, because the Recycle Bin would take another file for it. So does deleting a file or folder whose path is longer than about 260 characters.
• Signing out, shutting down or restarting Windows, and an installer that closes Cairn through Restart Manager (Cairn's own installer included), end Cairn at once, without the save that closing the window makes. Edits typed since the last autosave are lost, and so are edits that Cairn could not save, without the Unsaved changes question. After Alt, F10 or Alt+Space (see below), the autosave waits too, so more can be lost.
• After a note or a folder is renamed only in case (note.md to Note.md), in Cairn or in File Explorer, the file tree can list it under both spellings. The old spelling goes when Cairn next reads the whole notebook: at the next sync, or when the notebook is opened again.
• Two Windows or macOS devices can spell one folder differently, for example Drafts on one and DRAFTS on the other, also after a case-only rename of the folder in Cairn or in File Explorer. Each device keeps its own spelling, and sync no longer moves the folder's notes back and forth. A new note goes up in the spelling of the device that made it, so a Linux device gets a folder for each spelling. On a phone with the notebook in shared storage, a new note that comes from another device into a folder that the phone has under another spelling is not stored there. It is listed under "Files not synced" (see Android, below). Cairn 1.3.1 and older still move such notes back and forth, so update every Windows and macOS device that syncs the notebook.
• Cairn lists and syncs files that Windows marks as hidden or system files, such as desktop.ini and Thumbs.db, like any other file. Only a dot at the start of a name hides a file.
• Saving a note that has hard links replaces it with a new file, so its other names keep the old text, because the standard library cannot read a file's link count on Windows.
• A save from an open tab checks the note again just before it replaces it, but on Windows that check compares only the size and the modification time. Another program's save in that moment that keeps both (cp -p, rsync -t, a backup restore) is written over.
• A note that another program keeps open without allowing it to be replaced cannot be saved until that program closes it. When the program lets others read or write the note, Cairn says it has no permission to access the note. When the program allows no sharing at all, Cairn says "The process cannot access the file because it is being used by another process." Once the program closes the note, the edit is saved at the next keystroke or with Ctrl+S, not by itself. A change that sync brings for the note waits until then and is listed under "Files not synced". As in File Explorer, the note cannot be renamed, moved or deleted while it is open: Cairn then says that the file is being used by another process.
• A file whose name no Windows file can have, made on another system on a drive that Windows also reads, is left out of the notebook and not listed under "Files not synced".
• A notebook on a network share (\\server\share), also one opened through a mapped drive letter such as Z:, shows and keeps its folder with a \\?\UNC\ prefix, for example in the list of recent notebooks. A path longer than about 260 characters keeps its \\?\ prefix in the same way. Open in default app and Reveal in file manager work on shares and mapped drives. Reveal in file manager shows the file in File Explorer under its \\server\share path, also in a notebook opened through a drive letter. For a path longer than about 260 characters, or with a name that File Explorer cannot handle (one that ends in a dot or a space, or is a device name), Reveal in file manager shows an error that says File Explorer cannot show it. Open in default app on a file at a path longer than about 260 characters starts the app, which may then fail to open the file. Notepad, for example, says "The system cannot find the path specified." Cairn shows no message.
• WebView2, the web view Cairn runs in, no longer acts on its browser keys, except its zoom keys. So F5, Ctrl+R and the other reload keys no longer reload the window, and in the reading view, Ctrl+F no longer opens WebView2's find bar. Cairn has no search of its own in the reading view: press Ctrl+E to edit the note and use Ctrl+F there, or search the notebook with Ctrl+Shift+F. The right-click menu keeps only Emoji, its editing items (such as Undo, Cut, Copy, Paste and Select all), the spelling suggestions, Copy link and Copy image. Elsewhere, WebView2 shows no menu of its own on a right-click. The file tree still has Cairn's own menu. With a WebView2 Runtime older than 120.0.2210, WebView2 still acts on its other browser keys. The reload keys are taken from it and from Cairn too, so a hotkey set to F5 or Ctrl+R does not run there.
• After Alt is pressed and released on its own, after F10, or after Alt+Space and then Esc, the window waits for a menu key, with no menu in view, and the web view waits with it. A save then waits until the next key press or click in Cairn, and the next letter typed is taken as a menu key, not typed into the note. Switching to another window does not end this. Press Esc or click in Cairn.
• In the editor, Ctrl+Shift+Z does not redo; Ctrl+Y does. Text fields, such as the search box, take both.
• Characters typed with AltGr, such as @, €, {, }, \ and ~, type as they should: WebView2 reports AltGr as its own key, not as Ctrl+Alt. On a keyboard layout with AltGr, Windows turns Ctrl+Alt with a key into AltGr with that key, so a hotkey of Ctrl+Alt with a key that types a character there, such as Ctrl+Alt+Q on a German layout, which types @, cannot run. No default hotkey uses Ctrl+Alt.
• Each notebook's sync settings, the server token, the notebook key, the sync state, the copies of synced notes kept for merging, the plugin approvals and the list of recent notebooks are in the roaming AppData folder. Where roaming profiles are in use, Windows copies that folder to the other computers the user signs in to. A plugin turned on for a notebook there is then approved for a notebook at the same path on those computers: it runs there without being turned on again if that notebook lists it and the plugin file is the same.
• The file watcher kept up in testing: 20,000 files made outside Cairn in one burst, and then 3,000 renames, all showed in Cairn within about 3 seconds.
• Found by reading the code, and not tried yet:
  • When even more files change outside Cairn at once, the file watcher can miss some of the changes without noticing. After an error, such as a network share that drops out, it can stop watching the notebook until the notebook is opened again. Cairn finds the missed changes at the next sync, or when the notebook is opened again.
  • Copying the roaming AppData folder to other computers, with a roaming profile, was not tried.

macOS and iOS

• Cairn has not been built, tested or run on macOS, CI does not cover it, and releases have no macOS build.
• There is no iOS app.

Android

• Shared folders refuse a name that differs only in case from an existing one, and names the storage cannot hold. A file synced from another device under such a name, or into a folder whose name differs only in case from one on the phone, is not stored on the phone and is listed under "Files not synced" (FINDING-031, FINDING-172).
• Of two notes whose names differ only in case, the phone stores one in the shared folder and lists the other. When another device renames a note to a name that differs only in case from another note on the phone, the phone holds the rename back and lists it. Edits made to that note on the phone stay on the phone until one of the two notes is renamed or deleted. If the phone already has a copy of another device's note in a folder whose name differs only in case from that device's folder, the copy syncs as a second note, because taking it for that note would mean renaming the folder on every device. Nothing is lost in any of these cases (FINDING-172).
• When another device moves some notes into a folder whose name differs only in case, the phone renames the whole folder, on every device (FINDING-034).
• Shared folders have no atomic replace: a kill during a save can leave the new text followed by the end of the old, never a shorter file, and a kill during a move under a new name can leave the note under an intermediate name (FINDING-026, FINDING-033).
• After a renderer crash, text typed within the autosave delay is lost (FINDING-176).
• On Android 17, Cairn asks for the Nearby devices permission only for a server whose address is private, in 100.64.0.0/10, link-local or IPv6 unique local, or whose name ends in .local. Android also counts as local an IPv6 address on a directly connected route, such as a public IPv6 address on the phone's own network. Sync to such a server without the permission times out after about 30 seconds, and the message then says to allow Nearby devices in Android settings; Cairn does not show the prompt for it. A server on the local network that is down, or that the phone cannot reach where it is (on mobile data, or with the VPN off), fails the test connection too, so without the permission Cairn then asks for it, or a background sync says it is missing, although the server would not answer anyway. Cairn cannot tell for sure that a timeout came from the missing permission (Android reports that only through android_getnetworkblockedreason on the socket, which the HTTP client does not expose).
• Cairn cannot open files in other apps yet, images included. Images open in a tab inside Cairn, and a tap on another attachment shows a message. In Live Preview a tap on an embedded image edits the embed, so the image opens from the reading view. An image in a shared folder is read whole through the Storage Access Framework before it shows, so a very large photo there takes a while to open.
• Shared folders are slower than the app's own storage for large notebooks.

Plugins

• Approvals are per device and per exact file content, so editing a plugin or moving the notebook turns it off until the user turns it on again.
• Plugins have no memory limit: Cairn sets none, and a web worker cannot be given one. A plugin that keeps allocating can end the web view's process; on Linux the window then goes blank (FINDING-161). This has not been tried on Android or on Windows.
• Cairn stops a plugin and turns it off when a command runs over 30 s, the plugin misses three pings or it floods the app with messages. The only way to stop a slow command is to turn the plugin off (FINDING-069, FINDING-153, FINDING-156, FINDING-162).
• A plugin has at most 200 commands and 16 API calls in flight, and at most 5 toasts show at once (FINDING-072, FINDING-157, FINDING-162).

Core plugins (1.1.0)

• Their switches and options are in .cairn/settings.json, which Cairn sync does not copy, so with Cairn sync they are set up on each device.
• Day and month names in dates are always English, so that devices with different system languages give a daily note the same name.
• In a daily note's template, {{date}} and {{time}} use the date and time formats of the Templates plugin, whether it is on or not.
• There is no option to open today's note when a notebook opens: nothing is created by opening a notebook.

Themes (1.2.0)

• Cairn 1.0.0 and 1.1.0 show Limestone or Slate in a notebook set to Marble or Graphite. They keep the choice, so it comes back in 1.2.0 and later.
• On Android, the area behind the status and navigation bars follows the system's light or dark mode, not the theme chosen in Cairn. On the desktop (tested on Linux), the window's title bar does the same.
• In Limestone, Marble, Slate and Graphite, scrollbars, horizontal rules and graph edges are below 3:1 against their background, and the highlighted entry of the command palette and quick switcher, the selected version in version history and pressed panel buttons show only as a tint or a color. Since 1.3.0, the high-contrast themes keep scrollbars, horizontal rules and graph edges at 3:1 or more, and draw rings and bars of at least 3:1 for those states.
• A CSS snippet can change any color, so it can bring a theme below its contrast.

High-contrast themes (1.3.0)

• Cairn 1.0.0 to 1.2.0 show Limestone or Slate in a notebook set to a high-contrast theme. They keep the choice, so it comes back in 1.3.0 and later.
• The high-contrast themes do not follow the system's high-contrast setting; they are picked in Settings. WebKitGTK reports that setting only for a GTK theme named HighContrast, and Android's web view does not report it. What a Windows contrast theme does to Cairn's colors has not been tried.

Font file (1.3.0)

• A notebook has one font file. The web views draw bold and italic text from it by thickening and slanting the regular letters, also when the file is a variable font.
• Cairn sync does not copy .cairn/, settings included, so another device uses the Text font until the font file is picked there too. Copying the file alone is not enough: the device's own textFont setting names it. Cairn 1.2.0 and older use the Text font too.
• A font file picked under the name of the one in use (ignoring case) is saved over it; one of another name replaces it and the old one goes to the trash.
• The web views use only the first font of a collection, so ttc files are refused. Android's web view and WebView2 on Windows check fonts more strictly than WebKitGTK, so a file that loads on Linux can fail on a phone or on Windows; Cairn then uses the Text font and says why.

Editor and app

• Live Preview reveals the syntax of the whole line under the cursor, not of one element at a time. Callouts, math and footnotes are not rendered in any view: a callout shows as an ordinary quote, and math and footnotes as plain text. In the reading view, a footnote whose text is only a link or one word is read as a link definition: its line does not show, and its marker, such as [^1], shows as a link. Raw HTML blocks show as text in Live Preview, except in an embedded note, and render in the reading view. Script, style and iframe tags never render, and a form tag is dropped, so a form's fields show but send nothing.
• The properties panel is read-only; properties are edited as YAML in the note.
• A right-click in the box where a name is typed to rename a file or folder in the file tree shows the file tree's menu, not the editing items, and renames it to the name typed so far.
• The graph shows the whole notebook only: there is no local graph, and no filter other than for unresolved links.
• The status bar's word counts of Thai, Lao, Khmer and Myanmar text come from the web view's dictionary (ICU), which is not the same in WebKitGTK, in WebView2 on Windows and in Android's web view, so they can differ a little between devices.
• On Linux, a SIGTERM to the app saves open notes first, as closing the window does, and the app exits at most 3 s later. When every process of the app gets a signal at once (systemd does this at logout or shutdown, and so do Ctrl+C and a closed terminal), the web view goes too, and the edits made since the last autosave are lost. SIGKILL or a crash loses them as well. Autosave runs 600 ms after the last keystroke (FINDING-009).
• Unsaved edits are merged with a change on disk unless the changes touch the same or neighboring lines or either side rewrote more than about 10,000 lines (more than 20,000 lines added and removed); then the tab shows the banner that says the note changed on disk. Lines only added or only removed in one place, and a reordering of many lines, are not counted; a reordering can still make the merge slow, about 1 s for 20,000 reversed lines in a release build (FINDING-074, FINDING-151).
• If a note with unsaved edits is deleted outside Cairn and another note is then renamed onto its path in Cairn, two tabs show that path. "Save my version" in the first tab then shows the banner that says the note changed on disk, and that tab replaces the renamed note only if the user picks "Keep mine (overwrite)" (FINDING-010).
• Only http:, https: and mailto: links and a fixed list of file types (documents, images, audio, video, archives, and text files such as txt, csv, svg, json, yaml, ics and vcf) open with the system's default app. Web pages, XML and Office files with macros (html, htm, xml, docm, xlsm, pptm) do not. Windows opens svg in a browser, and old doc, xls and ppt files can hold macros (FINDING-066).
• The editor's highlighting ends frontmatter only at an exact --- line (FINDING-052, FINDING-085).
• Editor keys such as Mod+Enter or Mod+D can be recorded as hotkeys, and then the editor does not get them (FINDING-096, FINDING-214).
• The zoom keys cannot be rebound. On Linux, the zoom is not kept after a restart, and Ctrl+0 does not reset on AZERTY. On Windows the zoom keys are the web view's own: in testing, Ctrl with =, - or 0, Ctrl with + or - on the number pad, and Ctrl with the mouse wheel worked. Whether the zoom is kept after a restart on Windows has not been tried. Android has no zoom keys (FINDING-125).
• Toasts have no history, and an error toast goes 7 s after the pointer and focus leave it (FINDING-218).
• Screen readers hear sync errors, recoveries and conflict counts, not each sync (FINDING-205).
• A nested folder moved to another parent right after an event on a file in it can be taken as a delete and a create (FINDING-129).
• Live Preview renders tables only as far as the editor has parsed (FINDING-043). When the editor runs out of time parsing a note, the next edit can hit a bug in @lezer/markdown that shows a code block's lines as plain text or a table and the text after the block as code, until the note is reopened. In testing, this took pasting a code block of about 90,000 characters or more a few thousand characters into a note, then one more edit (FINDING-225).

Performance

• On 50,000 notes the graph is slow. On a debug build, a hover takes about 0.35 s (about 45 ms on 10,000 notes), and the current look stays (FINDING-042). Opening the graph takes 1.6 to 2.4 s on that build, with a longest frame of 0.7 to 1.1 s, and about 0.9 s on a release build, with one frame of about 730 ms (FINDING-127). The debug build uses about 1.6 GB after hovering, and closing the graph brings that down only to 1.3 to 1.4 GB (FINDING-128).
• Sync uploads one file per request, so the first sync of a large notebook takes time in line with its number of files (about 5.3 s for 5,000 notes in the sync tests). Sending files in batches needs a change to the sync protocol (FINDING-126).