Inconsistent warp_mouse when used within unfocused window-manager popup

[Sauermann]

Godot version

v4.0.alpha.custom_build [b7850bb]

System information

Linux, Debain 11, Xfce, Nvidia, Vulkan

Issue description

warp_mouse does not work correctly within unfocused popup.
Within "Sun and Environment Settings", warp_mouse is triggered after releasing LMB after dragging the Azimuth slider.
This results in the mouse cursor being moved to the scene-tree dock.

I would expect, that after releasing the Azimuth slider, the mouse cursor appears at the Azimuth slider.

BugSpinSliderInPopup.mp4

DisplayServerX11::warp_mouse uses as reference Window the DisplayServerX11::last_focused_window.
It looks like the "Sun and Environment Settings"-popup window is not the DisplayServerX11::last_focused_window, but the main window is.

Steps to reproduce

1. Open Editor
2. Create Node3D
3. Open Sun and Environment Settings
4. Drag and release Azimuth slider

Minimal reproduction project

Editor issue