Describe the bug

When attempting to add additional text to a textbox using shift-insert (ctrl-v seems to work ok) the existing text in the box is completely replaced but worse than that, it breaks the undo for the textbox.

To Reproduce

1. Create a text box with some text.
2. Copy text from any source
3. Paste the new text using shift-insert.

Expected behavior

The new pasted text should be inserted into the textbox at the cursor insertion point taking on whatever text attributes are in place at the insertion point, unless some existing text is already selected.

Actual behavior

Any existing text is removed and the only the new pasted text remains.
In addition undo/ctrl-z does not restore the text prior to the paste command.

Additional resources

Don't know if it is pertinent, but I noticed the magnet icon is depressed (as expected) during the "shift" part of the hot-key.

It also appears that when shift-insert is used the action/modification to the textbox does not get added to the undo list (it does work with Ctrl-Z).

Context

• reproducibility : systematic
• OpenBoard version :
  • bug happens with : 1.7.3
  • didn't check : any other version
• OS :
  • bug happens with : Linux
  • didn't check : Windows macOS
• Installation source : snap

Additional context

• OS(es) detailed version (for the ones you reproduced the bug on)
  • Linux : Ubuntu 22.04.5
• number and resolution of monitors : 3
  • HDMI-0 connected 3840x2160+0+0
  • DP-1 connected 1920x1080+5760+1781
  • DP-2 connected primary 1920x1080+3840+1781
• if used, manufacturer and model of graphic tablet input device : N/A