Icon missing in the side panel

I see a weird situation that some icons are missing from the side panel. The sub-panel is still there but the tab button is blank. Public Build, 7.0.20007.12535, Git hash:master @ 9a18142843813da3d13399261d83b0264ea1ddca`

How to replicate:

  1. Launch Rhino WIP
  2. Launch Grasshopper, and some icons will be back

systeminfo.txt (2.1 KB)

Pic1: Tab buttons are blank

Pic2: New buttons appear normally

Pic3: After I launched GH, per-object icons are back, whereas the icons, when nothing is selected, are still missing.