Initial window size is wrong when launching GVim in a floating window

[vadz]

• Sway Version:

  • 1.10.1

• Description:

I'm using Sway 1.10.1 with GVim (9.1.1230) under Debian 13 (Trixie). I have something similar to (but this is simpler and sufficient to see the problem)

for_window [title="VIM"] floating enable

in my config. Now if I run

$ gvim -U NONE -c 'set titlestring=VIM' -geometry 40x30

GVim opens as a floating window with the size that it would have if it were maximized. Toggling its floating state twice gives it the expected geometry, bot on startup it has 237 columns and not 40 as expected (same for the number of lines).

I'm not 100% sure if it's a Vim or Sway bug, but I've only started to see this happening since upgrading to Sway 1.10.1 from the old 1.7.6 that was used in Debian 12 (Bookworm). I was running my own GVim binary, with Wayland support enabled by default, and the same binary didn't show this problem with 1.7.6 but does now. Please note that both Debian GVim package the latest GVim master also behave in the same way, and that this doesn't depend on whether GVim uses Wayland or X11.