I didn't understand your problem with windows. Would it possible that you send [url=mailto:[email protected]]me[/url] your file to help me fix this possible issue?

The oblique triangular surfaces come from the way ceilings are computed. Please read the help about rooms and avoid use small walls near room ceiling points.

I just tried to double click on furniture lines and didn't have problems. Maybe your system have a very short double click delay, then you should try to double click faster.

If you want to increase the text of dimension lines (and any other text), select them and use Plan > Modify text style > Increase size menu item.

Did you build your 11 m model with the version 3.4 Beta or with the version 3.3?