Very cool idea to let the user mark an area before selecting widget, rather than the reverse, which is more or less the standard way. It works well. I would su

Very cool idea to let the user mark an area before selecting widget, rather than the reverse, which is more or less the standard way. It works well. I would suggest that you save state in local-storage and/or hook into the onunload event, to prevent people from accidentally abandoning a sketch.