Detailed Description of the Problem Let's imagine you are building walls out of polygons. You group some of them, so that you can move them somewhere. Then you want to add more polygons to the group. If you try to do this, the first (already grouped) polygons get teleported to the upper-left corner of the tabletop (but they do get grouped). Very, very occasionally, this works as intended, and I don't know why. Steps to Reproduce the Problem In this screenshot, I've already drawn a black box and a line across the diagonal, and grouped them. I'm about to group the red line with the already-grouped black pieces (also note the poor alignment of the "group/ungroup" with "Advanced" which makes it really hard to mouse to either option): And then I click the mouse: Now you can see the box has launched over into the corner of the map (I'm guessing that's 0,0?). Description of Your Setup (Browser + Version, Operating System, etc.) Sorry about the bold. It's Google Chrome (whatever version it's at on 5/14/2013), Windows 7 x64.