My screenshot and canvas don't match, but I'm running Chrome. Same thing happens in Firefox, so it's probably the OS. I'm running Windows XP with two LCD monitors. ClearType was off so I turned it on, and that seems to have fixed it.

There's a bug when selecting items with a box when the cursor leaves the canvas. It would also be nice to set a new default font.

I was looking for a good web page mockup tool last weekend, but couldn't find one. I know HTML though and went with a good editor.