On my Windows 11 partition with the same version of Thunderbird Ctrl/+ also does not work, and you still need to hold Ctrl while scrolling. This is probably just a Thunderbird issue and not OS-related.
I'm on Fedora Linux 39 using Thunderbird 115.6.0 as a Flatpak and this issue is still present. The fix of just clicking on the View menu and then doing Ctrl/+ works, but what is working for sure is holding Ctrl while moving the mouse wheel up/down fo...
