Add the ability to mark specific windows to be visible on all workspaces

[sosasees]

Describe the project you are working on

taskbar and start menu for Linux (X11)

Describe the problem or limitation you are having in your project

the windows belonging to taskbar and start menu should be on all workspaces
but i can't find a way to do this in Godot

Describe the feature / enhancement and how it helps to overcome the problem or limitation

the ability to put windows on on all workspaces is needed so taskbar and start menu work like they should

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

there should be two ways to do this:

• for individual windows during runtime, this could be set a method in the Window class — probably always_on_current_workspace
• for all windows from the start, this could be set in an advanced project setting like /display/window/always_on_current_desktop

If this enhancement will not be used often, can it be worked around with a few lines of script?

i could pin the windows to all workspaces manually
but i failed to find an automatic workaround with a bash script that runs on autostart (called from ~/.xinitrc).

the manual workaround is:

1. list all windows with wmctrl -l
2. raise the windows i want with ``wmctrl -i -r <WINDOW_ID> -b add,sticky

Is there a reason why this should be core and not an add-on in the asset library?

so developers can add the project setting override — likely /display/window/always_on_current_workspace.editor — if they decide that keeping the debug game on all desktops makes playtesting easier:
for example quickly switching to Desktop 2 for playtesting so the playtesters can't peek the source code
and then switching back to Desktop 1 for continue developing.