Inspector: Border glitches in Objects
This looks pretty weird, especially since there's a border around the sidebar.
The Actions page comes with its own border at the top of the table header so that looks fine, but it has double borders at the bottom and on the vertical lines:
The Properties page has no border at the top of the table header, and there is only one double border, on the left edge:
Also: The table headers in Properties and Actions seem to be different heights.