First let me say, I have lusted after the ability for MC to incorporate dragging tabs to reorder them, and also being able lock them against accidental overwrite, so thank you for incorporating these wonderful enhancements.
That said, if one is not careful to drag the tabs in a straight line at the same level as the other tabs, disaster lurks with a slip of the mouse. I was dragging my panes tab to reorder it (with my entire library active) and accidentally "let go" of the tab while it was over the artist pane, but slightly below the tab row. MC immediately began to re-tag my entire music collection to the artist I "dropped" it on (Rod Stewart in this case). I did not notice initially, but MC seemed to be hung-up, and after a minute or so I realized it was rewriting tags. I hit undo, and that seems to have reversed my error, but not before it was well on its way to overwriting tags for 22K+ files!
Dragging any tab outside the tab row "envelope", even into the playerbar, MC tries to do stuff (copy, play, etc). I did not experiment too much, as I did not want to accidentally cause catastrophic damage to my library/tags. I don't know if this is intended behavior or a bug, but it seems to me the only thing tab dragging should do is move it to another position without attempting to perform tagging or other operations based on where it might get dropped. It should also only only honor horizontal mouse movement and ignore the vertical mouse movements altogether while dragging a tab.
