MuseScore 3.0.2.5315 - cannot drag & drop items from the tools palettes

When I click an item from the a number of the tools palettes (time signatures, key signatures, accidentals, articulations, grace notes) to drag it to my score, I immediately see a red circle/slash graphic, and while I can drag the selected object to my intended target it will not drop on that target. See attached image file showing this behavior.

Interestingly, not all the palette object behave this way - dragging and dropping clefs, key signatures, time signatures, grace notes, lines, and barlines all drag and drop as expected. This would seem to suggest that this is not some OS/system issue, but something in the MuseScore code. This is further supported by the fact that when I launch my still installed copy of MuseScore 2.3.2 this drag and drop of all palette still works perfectly.

I use this drag & drop functionality extensively in my workflow, so this problem is pretty annoying.

Anyone else seeing this? Is there some configuration setting that's new to MuseScore 3 that I need to modify? Is this a bug in the code?

Thanks,
John