Drawing in image tiddlers - Eraser? Undo?

[Brad DeBruler]

I just started playing with image tiddlers to draw quick diagrams as opposed to linking/displaying images inline. Is there any eraser option that I am failing to see? I also was hoping I could use undo (ctrl-z), but it doesn't work as I hoped.

Please let me know if there's something I have overlooked or if you know of any good plugins that might give me what I want. I'm not expecting photoshop, I was excited that this function was here at all and I just noticed it!

Thanks!

[Morgaine O'Herne]

Would also love to be able to erase.