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

The problem resolves itself when I launch in safe/troubleshoot mode. Any next steps you'd propose such that I can still use the link function without having to constrain myself to always using safe mode? Thank you!!!

Launch in safe mode, at the prompt: 'Reset toolbars & controls', 'Make changes & restart'. If that doesn't help, launch in normal mode, disable hardware acceleration in Settings/General, restart TB, test the link dialog.

I have reset the toolbars & controls. This works. Unfortunately, sporadically (rarely), the problem reappears. I'm using 115.5.1, 32-bit, on Windows 10.

Did you disable hardware acceleration? Are you using the default theme and any add-ons?

I use the default theme and two add-ons (ImportExportTools NG & ThreadVis). Since the resetting trick works for weeks, I have not disabled hardware acceleration. I can disable it if that would help locate the issue. Probably I will have to wait a couple of weeks. Can the issue be analyzed as it happens, i.e., when the dialog is not displayed?

By the way – and for any search engine visitors – pressing Esc closes the invisible dialog box, which unfreezes Thunderbird.

Is hardware acceleration currently enabled in normal mode? I think you can safely disable it if it's on. It practically never improves performance, and very often degrades performance. Note that in safe mode it's disabled and a default layout is applied, so resetting the layout or disabling acceleration, or both, eliminates the freezing.

Yes, hardware acceleration is enabled in normal mode. I have now disabled it. If the freezing issue reoccurs, I will report back.

I had the same problem and it was caused by the dialog opening off-screen. I then used the keyboard controls (on Windows: Alt+Space) to open the menu "Move" to then use the cursor keys to move the window to the current screen.

It seems to me the Thunderbird memorized a screen position from when I had a second screen connected to my laptop. I'd wish that T. would check that it opens the dialogs never off-screen.

(Update: I use version 115.7.0)

I had the same problem and it was caused by the dialog opening off-screen. I then used the keyboard controls (on Windows: Alt+Space) to open the menu "Move" to then use the cursor keys to move the window to the current screen.

Thank you so much, this is exactly what helped me. Insted of using the cursor keys you can also follow up the Alt+Space by maximizing the dialog window.