breakage when trying to enter Unicode character using ctrl+shift+U just after emoji

[qcGVkzEG]

Using a supported version?

• I have searched searched open and closed issues for duplicates.
• I am using Signal-Desktop as provided by the Signal team, not a 3rd-party package.

Overall summary

On Linux (Wayland), trying to input a Unicode character between an emoji and some other character causes the UI to break. (See explanation and screenshots below.)

Steps to reproduce

1. Compose a message which contains an emoji entered using the :something: shortcuts, and some more characters afterwards. (The bug does not occur for emoji that were entered directly as Unicode characters.)
   
2. Move the cursor just behind the emoji and press ctrl+shift+U to enable Unicode input.
   
   At this point the rendering already starts to break (normally only the 'u' is supposed to be underlined):
   
3. Try inputting a Unicode codepoint in hexadecimal. Normally, upon pressing the space bar, the "uXXXXX" sequence should be replaced by the corresponding Unicode character. Here, however, no replacement occurs:
   

Expected result

Inputting the Unicode character using ctrl+shift+U should work.

Actual result

See above in "steps to reproduce".

Screenshots

No response

Signal version

7.38.0

Operating system

Linux (Wayland)

Version of Signal on your phone

No response

Link to debug log

No response

[scottnonnenberg-signal]

Ah, that's unexpected - sorry about that. Does that Ctrl+Shift+U shortcut work as the first thing you do in a text box? What might be happening is that the emoji is not considered text, so you're essentially in a new text box right after the emoji.

[qcGVkzEG]

Thanks for the quick reaction! It works correctly with the cursor at the very beginning of the text box (in all cases, that is, with or without other characters following the cursor).

[scottnonnenberg-signal]

What about right after an emoji and a space?

[qcGVkzEG]

For [emoji][space][cursor][whatever] it all works as it should. The precise condition I seem to have identified is: Just after an emoji that was entered using a :something: shortcut, followed by another character.

[scottnonnenberg-signal]

Thanks for the additional investigation!