Bug report: LyX hangs when copying an inline formula containing \mbox{\,}

[Léo de Souza]

Hello,

I would like to report that LyX hangs when copying an inline formula containing a thin space in an mbox.

Environment:

I compiled LyX 2.4.1 on Ubuntu 22.04 with Qt6 enabled.

Steps to reproduce:

1. Create a new document: File > New
2. Create an inline formula: Insert > Math > Inline Formula
3. Type \mbox and space to create an mbox
3. Type \, to create a thin space in the mbox
4. Copy the formula

Expected result: The formula is copied to the clipboard.

Actual result: LyX hangs and its CPU usage jumps above 90%.