First of all - great done.. I've just started writing my own editor for my little isometric 2D adventure game when I stumbled onto this.. Many thanks..
Now to the critcism:
The isometric tile system is pretty useless atm.. But.. If you want to I've altered the source to overcome this problem..only a fast hack, but it was only done for my own usage right now, evene if it should be fairly easy to implement in a more proper way.. I changed the tile cutting mecahnism to cut proper isometric tiles and render them using a bitmask so you get rid of the overlapping regions.. I also, mostly due to me beeing lazy, changed the image loading routines so that it now uses javax.imageio.. All my tilemaps where in bmp format
I also had to change the tile palette window, because when you're dealing with isometric tiles, it looked like a pretty advanced puzzle - it now draws every "odd" line in offset to the other line, so the tiles line up properly..
The only con so far is that I haven't been able to change the editor so it accepts isometric tiles with a 4:3 format, wich is what I use.. It works great for 1:2 tiles, but I'm at it right now.. Keep it up!