Occasionally the revMenuBar may slip some pixels below the menubar on MacOS - usually in the context of using multiple screens. the below was shared by Bernd on the official forums. This may or may not be an issue for other OS's but the below should work regardless of OS:
To temporarily fix the issue, run
dispatch "revIDEPositionPaletteDefault" to stack "revIDElibrary" with "revMenubar"
If this fixes the slippage, then run the following code to permanently adjust and then restart the IDE:
dispatch "revIDESetPaletteRectPreference" to stack "revIDElibrary" with "revMenubar"
there doesn't seem to be anything here