Today I commited the last batch of fixes for Boo scripts for this release - you can find the changes here.
I've fixed two bugs that were affecting the lock feature for line length and circle radius, and improved the property grid for mouse drag. After this change, if a line is resized, the length property is automatically updated, without needing to re-select the shape.
I've also started improving the Point to point and Point to Edge constraints, so that we can update the distance and control shape positioning this way. I've updated the Point to Edge property tab and the dimension display:
The next step is to allow the user to update the distance and update the shapes' positions through the Solver.