I can't reproduce it in 115.3.2/W11. Ctrl+I (eye) toggles italics, without affecting the cursor.

Does the same thing happen in safe/troubleshoot mode (hold Shift when launching TB)?

I just updated to 115.3.2. The problem is still present. Specifically, it's true that "Ctrl+I (eye) toggles italics", but whatever key I press next sends the cursor back to the beginning of the line of text. The italics is turned on in the location I was selecting, but the cursor is no longer there.

Is there an ETA for Mozilla fixing this vexing malfunction? I've searched; I've tried the Troubleshooting fix (it doesn't fix); I've tried updating. I'm not ready to uninstall and reinstall Tbird in order to back up to an earlier update. Seriously, this makes me leery of ever accepting another update, when it might introduce a broken basic function. I'm just hoping the solution is on the way! Seeing this stalled at 10/17 (nearly a month ago), my heart sinks. Note: I supported Mozilla with a donation just last month. Please apply my donation to fixing this!

If you think this is a bug, you can report it on Bugzilla, including a link to this topic. Before doing so, I recommend doing a test in a new profile with just one account. Help/Troubleshooting Info, about:profiles, to create and launch profiles.