Using Quick Add sometimes "crashes" 1.5

Hi,

This version adds a lot of new widgets, such as the Groupbox, and I find it overall to be of an excellent quality.

I'd like to report on a small problem though. Sometimes, when I hide the UI library and select a widget by entering its name, and then click on one of the suggested names, the whole screen becomes grey and I can't interact with anything else until I Undo my change. I have not seen this behavior when dragging UI elements from the UI library. This doesn't happen very often, maybe 1 out of 15 selections.

Keep up the good work.

Luc