Window Snapping not working for GTK3 apps

Describe the bug
BTT's "window snap" feature does not work (there is no "snap") with GTK3 apps on MacOS Mojave and Catalina.

To reproduce the bug, install a GTK3 app, e.g. Zim

brew install zim

Open it, and test the snap functionality with zim's window (e.g. 1/2 screen tile, by dragging the window to the left or right screen edge) and confirm it doesn't work :slight_smile:
FWIW, windows of older GTK2 apps e.g. older versions of zim were working fine with BTT window snapping.

Affected input device (e.g. MacBook Trackpad, Magic Mouse/Trackpad, Touch Bar, etc.):



Device information:

  • Type of Mac: Macbook
  • macOS version: Catalina 10.15, however the same problem was happening in all Mojave versions. I haven't tested earlier versions of macos.
  • BetterTouchTool version: all versions - this never worked

Additional information (e.g. StackTraces, related issues, screenshots, workarounds, etc.):

sorry, unfortunately this is a general problem with such apps, as they don’t implement the macos standard window APIs correctly.
Most likely there won’t be a way to fix this, but i’ll have a look at the app you mentioned.

Probably the developers of GTK3 would need to implement the required API