The current thickness is also shown when dragging as well.
Closing the ruler thing and reopening will recreate the component, so the Width/Height text will reset.
I could use `Qt.binding(funtion(){ return panel.thickness })` but I don't think the panel will procedurally change with the panel's config open.
Bug 372364: https://bugs.kde.org/show_bug.cgi?id=372364
Reddit: https://www.reddit.com/r/kde/comments/65wdow/can_we_get_some_support_for_pixel_perfect_panel/
Here's a demo: https://streamable.com/m2o7c
Not intended:
Moving the panel's screen edge triggered the `panel.onThicknessChanged`
Demo: https://streamable.com/8jof7
The best way to fix that is probably setting `button.text = panel.thickness` in the mousewheel event and in every case in the "drag" onPositionChanged event. Unless someone else can think of something better.