Moving xfce4-panel doesn't work very well

Issue Description

Basically, the panel doesn't really follow the pointer; it “escapes” pretty quickly and ends up sticking to one edge or another of the screen.

I had managed to use layer-shell margins to follow the panel’s original X11 code path fairly closely (notably panel_window_motion_notify_event), and it hadn’t worked too badly up until now, especially on labwc, but also pretty well on wayfire. On tiling compositors, it generally doesn’t work as well (sway, for example, if I recall correctly), and I find that the rendering in xfwl4 looks a bit like that, actually.

Maybe it could be improved? I don’t think I can do much on the panel side, and I’d prefer to keep the same code path for both X11 and Wayland.

Steps to Reproduce Issue

  1. Launch xfce4-panel
  2. Uncheck "Lock panel"
  3. Move the panel by grabbing one of its handles

Expected Behavior

The panel moves smoothly with the pointer, just like on X11 (at least when staying on the same monitor).

Additional Information

Environment & Versions

  • OS distribution and version: arch linux
  • Overall Xfce version: 4.20
  • xfwl4 version (git hash if not a release): 4.21.0+107+g643aa74
  • libxfce4ui version (git hash if not a release): 4.21.8
  • xfce4-settings version (git hash if not a release): 4.21.2
  • GTK theme: Adwaita
  • Decorations theme: Default
  • GPU make and model: AMD/ATI Radeon HD 7310
  • Monitor scale factor(s): 1