Running svn version 1789 on ubuntu...
I did some experiments. If the only plugin I load is libcompiler, I can close projects fine. The cursor is not "waiting" anymore. I get the start-up screen in the editor. Everything is fine.
With libpluginwizard as the only plugin, the same is true: projects close OK.
With libastyle alone, projects close OK.
With 2 or more plugins ( just about any 2), I can't close a project. Get the "waiting" cursor. Editor screen is cleared but the project tree remains...
So it appears that something about plugin management is the culprit here. I have tried to isolate to a single plugin but with just about any 2 or more installed, then closing a project is a problem. With only one, all is well.
Hope this is helpful to someone.