Some pop up windows appear on the wrong monitor when code or shader editor are floating on the second monitor

[Tetane]

Godot version

4.1-rc2

System information

Windows 10, Two monitors

Issue description

The "Create shader node" window is appearing inside the boundaries of the main Godot editor window instead of the visual shader editor window when it's floating. Trying to fix this in #78996.

The "Search Help" window of the script editor always appears on the first monitor, even if the editor and/or the main Godot window is on the second monitor.

Steps to reproduce

Make the visual shader editor floating. Put the window on a second monitor and right click to open the "Create shader Node" window.

Make the code editor floating, put it on the second monitor and open the "Search Help" window.

Minimal reproduction project

N/A

[trollodel]

I think all popups always assume that there is only one window. They are usually relative to the right node, for this reason they are luckily placed in the right place. But not all, and some popups are placed in the main window, following it.
See this comment for a possible solution (this is for the progress dialog, but it's not the only one with that issue).

Side note: I had this speculative suspect while I worked on multi window support for code editors, but doesn't appear evidently to me in my tests.