Some note types such as Text and  Code notes in Trilium can be set to read-only. When a note is in read-only mode, it is presented to the user in a non-editable view, with the option to switch to editing mode if needed.

Automatic read-only mode

For optimization purposes, Trilium will automatically set very large notes to read-only. Displaying such lengthy notes in editing mode can slow down performance, especially when editing is unnecessary.

This behavior can be disabled on a per-note basis, by following the instructions of the next section.

In addition, it's possible to change the number of characters at which the automatic read-only mode will trigger in Options by going to the options for  Text Notes and Code Notes.

Changing a note's read-only behavior

A note's read-only behavior can be changed via:

• On the New layout, Note buttons → Editable on the new layout
• For the old layout via the Ribbon, by going to the Basic Properties tab and looking for the Editable selection.

The following options are possible:

• Auto
  This is the default behavior in which the note will be editable by default, unless it becomes large enough to trigger read-only mode.
• Read-only
  The note will be always marked as read-only, regardless of its size. Nevertheless, it's still possible to temporarily edit the note if needed. This is generally useful for notes that are not prone to change.
• Always Editable
  This option will bypass the automatic read-only activation for this particular note. It's useful for large notes that are frequently edited.

If the Editable section is missing from the ribbon, then the note type does not support read-only mode.

Manually setting the options

Apart from using the ribbon as previously mentioned, it's also possible to use labels to change the behavior:

• To set as read-only, apply the readOnly label to the note.
• To disable automatic read-only (always editable), apply the autoReadOnlyDisabled label.

Temporarily editing a read-only note

When accessing a read-only note, it's possible to temporarily edit it by:

• Pressing the Read-only badge on the New Layout.
• Or pressing the button in the Floating buttons area.

When pressed, the note will become editable but will become read-only again after navigating to a different note.

Special read-only behavior

Some note types have a special behavior based on whether the read-only mode is enabled:

• Mermaid Diagrams will hide the Mermaid source code and display the diagram preview in full-size. In this case, the read-only mode can be easily toggled on or off via a dedicated button in the Floating buttons area.
• Geo Map will disallow all interaction that would otherwise change the map (dragging notes, adding new items).