I'm using the perimeter circle sketch tool, and my circle seems not to be interested in staying on the points I'm drawing it on. Is this a bug, or am I doing something wrong? Sometimes it works, then breaks when I try to add another shape or line to the sketch. I've attached a simple example where I drew two lines, then a perimeter circle defined by the 3 points defining the lines. For some reason the circle does not want to sit on the points I've drawn it on. The second attachment is a successful example. It seems like the error is less likely to happen if I fully define the lines first.