Operating system: Windows 10, 64 bit
Graphics card: Intel inside
Broken: 2.80 release candidate 1
Operator panel occasionally fails to work/respond once an action triggers it's appearance.
The annoying thing about this bug is I haven't been able to reproduce it on demand, though it has happened two or three times. The most recent one was when I added a UV sphere in object mode. Trying to adjust it, I found that the collapsed (normal) operator panel had no text (abnormal), and clicking on the little arrow simply moved the 3D cursor; it was as if it was just an unresponsive overlay, not affecting the GUI at all. Deleting then re-adding the sphere triggered normal operation.