I don't know if it counts as a bug, but it is HUGELY frustrating (and upsetting at the moment since I just accidentally did it.)
I had a 4x4 grid of sprites sized 32px by 32px. I wanted to resize the tiles to 128px by 32 px so I did so, but I accidentally set it to center the content. Trying to fix my mistake, I resized the tiles back to 32px by 32px without clicking the keeping content in the center. Now it's all gone. Just have a 4 by 4 grid of nothing and I can't undo it.
I know this is my own stupidity for not saving more often, but it would be nice if information was retained in the file even when the tile is resized to something smaller than what it contains (if that makes sense.)
Also, why is it impossible to undo Resizing Tiles? That seems incredibly silly.