Seems like a bug. UI Toolkit Debugger only shows elements tree for me. Is there a way to enable the rest of the debugger's layout? Where I can inspect margin, padding, and the rest of the selected element? Unity 2020.2.0b12.3574
It's possible the inspector part of the Debugger is set to 0 width. You should be able to either re-expand it from the right edge of the Debugger window or temporarily make the Debugger window larger until the inspector part shows up.