I doubt if many or anyone will remember this but several weeks ago I thought there might be a problem with dragging shortcuts to IMatch favorites since I suddenly couldn't do it consistently any more.
Today I finally got to the bottom of the problem. It wasn't IMatch, it was an old USB hub I had plugged my wired mouse plugged into. Once I got rid of that hub and plugged the mouse directly into the computer all mouse related problems suddenly disappeared. :)
(https://www.photools.com/community/Smileys/photools/confused59.gif)