wrong terminal width on restart

[ekwf]

Describe the problem:
When tabby re-opens terminal tabs (i.e. restarting tabby altogether with running tabs) some of the tabs don't report correct $COLUMNS. This results in things like tmux and less not using the full screen width (this in turn causes display issues). Switching to window mode and back to max size while viewing that tab seems to fix it.

To Reproduce:
Run tabby and open several terminal tabs with tmux running (not sure if tmux is required).
Close tabby
Open tabby and tabs are restored
Re-attach to a tmux session and width is narrower than it shoudl be