Fix focus handling (attempt 2)

[iacore]

This resolves most focus-related issues.

[iacore]

The client side is working. The server side still need some work. QubesOS/qubes-gui-daemon#98

[iacore]

I hope this is the last fix about window focus before wayland.

[iacore]

Before 1c5b880: consistently buggy (when VM intra-transfer focus)

After: sometimes window will lose keyboard focus (mouse works fine). Minimize->maximize won't fix the problem. Have to click desktop when window is showing to fix.

Solution: have VM report window focus to dom0 QubesOS/qubes-issues#7403

[iacore]

Remaining problems:

1. Release all keys pressed after none of a VM's window is focused, like, 1 second after. (what keys are pressed could be tracked by dom0) By the time switched back, the VM should think all keys are released. Example: when VM think Ctrl + D is stuck, it close terminal immediately after you open one.
2. Decide which window has decoration, that we should give focus implicitly.
   Focusing every X "window" on click is working... mostly, except for VS Code's context menu, or Firefox's context menu. Leafpad's context menu works fine though. You cannot click on context menu with that attempt, so I didn't add this behaviour.

[iacore]

This is Problem 2 mentioned.

If anyone know how to do this properly, please send pull request to my branch (fix-focus-2)

[DemiMarie]

Windows have decorations if and only if they are not override-redirect. Context menus can just be not given focus.

[DemiMarie]

@locriacyber Would you mind splitting the PKGBUILD changes into a separate PR?

Remaining problems:

1. Release all keys pressed after none of a VM's window is focused, like, 1 second after. (what keys are pressed could be tracked by dom0) By the time switched back, the VM should think all keys are released. Example: when VM think Ctrl + D is stuck, it close terminal immediately after you open one.
2. Decide which window has decoration, that we should give focus implicitly.
   Focusing every X "window" on click is working... mostly, except for VS Code's context menu, or Firefox's context menu. Leafpad's context menu works fine though. You cannot click on context menu with that attempt, so I didn't add this behaviour.

Are these regressions, or are they problems with the current agent too?

[iacore]

They are new problems (recalling from memory, since I haven't use old agent for awhile).

Problem 1: Before this patch, key repeat was disabled in AppVM. Even if a key was stuck in AppVM, it won't generate stuff likeeeeeeeeeeeeeeeeee <- this.
Problem 2: I remember the old xside + vmside code send focus event to window on every click. I browsed the git history, but couldn't find a trace of the behavior "focus window on click".

@DemiMarie Can you try to reproduce this?

One way for you to reproduce problem 2 is (related: QubesOS/qubes-issues#7403)
In AppVM:

• In xfce4-terminal, type open "http://localhost/" while Firefox is open
• now Firefox should have focus, while Terminal is still on top of Firefox
• since Terminal doesn't have focus, the cursor should become outlined rectangle (instead of solid when focused)
• click anywhere in Terminal

It it was not buggy, the cursor should become solid, meaning Terminal has regained focus.

[iacore]

Superseded by #169