Comment 18 for bug 505765

The issue persists in 22.04. Not sure if it should be fixed in upstream: https://gitlab.gnome.org/GNOME/gtksourceview/-/issues/121.

However at least gedit behavior in Ubuntu 22.04 is better than in 21.10 (maybe fixed in new Gnome Shell 42.0).
Let's say you have a JSON file, not prettified, 1.9 MB size, whole content on one line. If you open the file in gedit, then:
21.10: gedit freezes (CPU 100% forever) and if you right click to app icon to dock, mouse and keyboard stops working and OS becomes unresponsive - you need to restart OS
22.04: gedit freezes (CPU 100% forever), but no OS freezing on right click in dock