[Bug]: Odd text handling with ckeditor-5

[DustinReynoldsPE]

What happened?

I'm seeing an odd issue. When I put my cursor in front of the 'T' in The, and I push the letter d,. It inserts dD.

When I <Shift+Enter> 't', the odd behavior occurs again.

When I make a new line, and type: "This is a test", when I push ". ", it jumps to the line above, like so:

This can be reproduced by trying the editor here: https://ckeditor.com/ckeditor-5/demo/feature-rich/

Thank you for the great plugin!

Steps to reproduce

See description for 3 examples.

Expected behavior

Plugin shouldn't insert characters inappropriately,. Or jump to a previous line.

Actual behavior

Plugin inserts characters inappropriately and jumps to the previous line when adding punctuation.

Browser

Firefox

FluentTyper version

2026.18.0

Operating system

MacOS 26.4

Logs, screenshots, or recordings

No response

[bartekplus]

Fixed in #357.

Root cause: FluentTyper's grammar edits and suggestion acceptance dispatched synthetic beforeinput events that CKEditor-5 intercepted but processed using its own stale model selection (not the programmatically-set browser selection). This caused duplicate characters, cursor jumping, and suggestions landing at wrong positions. Additionally, CKEditor-5's softBreak elements (from Shift+Enter) occupy 1 model offset but 0 text characters, requiring offset translation between DOM text coordinates and CKEditor-5 model coordinates.

Fix: Added CKEditor-5 as a recognized host editor (same pattern as the existing CodeMirror integration) by detecting element.ckeditorInstance and routing all text edits through CKEditor-5's model API (editor.model.change(writer => ...)). Key details:

• Detect CKEditor-5 via ckeditorInstance property on the editable element
• Map between DOM text offsets and CKEditor-5 model offsets, correctly handling softBreak elements
• Route grammar edits and suggestion acceptance through the host editor session
• Translate BR-separated line offsets to full-block offsets (with zero-width filler character stripping)
• Preserve text attributes (bold, italic) when inserting replacement text

All three originally reported scenarios (duplicate character insertion, odd Shift+Enter behavior, cursor jumping after . ) are resolved, along with additional edge cases discovered during E2E testing (suggestion placement on BR lines, formatting preservation, softBreak consumption).

[DustinReynoldsPE]

@bartekplus

Retested it with 2026.19.0:

Typed a single 't',. It produced this:

The bug where it jumped up a line seems to be fixed, but the 'tT' issue remains.