I was exploring with dragging a file to an IQ grid item and discovered that if the cursor passed over a vertical tab during the drag, no matter how briefly, IQ switched to that grid.  So I ended up dropping the item in the wrong grid.  Now if I realized the grid had switched, I could hover the cursor over the intended grid and switch back to it.  But maybe put in a small delay before IQ switches to a grid whose tab has been crossed over?