Do subsurfaces take keyboard focus upon click?
The spec does not say anything special about subsurface keyboard focus. In weston, clicking on a subsurface causes the keyboard focus to move to that surface, i.e., a wl_keyboard.leave and a wl_keyboald.enter event is emitted. In sway, clicking on a subsurface does not move the keyboard focus.
Firefox does not work in weston. When starting an audio or video call, a popup appears asking the user for permission to access the microphone. This popup is implemented using a subsurface. Clicking on Block or Allow has no effect under weston, i.e., the popup remains open.