I don't see a trouble shooting and bug report forum, so i'm posting this here, hopefully this is the right place to post.
anyway, I'm having a little problem with the Lascaux Sketch board. Somehow, if I click too much Ctrl+Z for redo, the board wouldn't let me draw anymore. The weird thing is, the board isn't really frozen either, I can still click on all the different icons, select different color, the only thing is that when i put down my tablet or mouse, nothing comes out. wheather it's the brush tool or eraser tool or bucket fill, nothing would change the drawing. It's as if my tablet and mouse is not touching the drawing. I tried to quit the drawing and start a new one, and same thing would happen if I undo too much at once (like maybe 5 or 6 undo). I know that maybe I press ctrl+z a little too fast, but I figured I should bring this up just to see if there's any solution.

just hit refresh and it'll reload lascaux with your image.
that's a known bug possibly related to tablet usage, or something, it's really hard to pinpoint since no one can reproduce it with very precise steps (nor can I). Reloading lascaux fixes it, but also messing with the brush settings should fix it (try clicking some from the tray).

thanks. i tried teh brush setting thing, but it didnt help. although reload always helps