- 
    Bug 
- 
    Resolution: Done
- 
    P2: Important 
- 
    1.2.2
- 
    VS2012 + update 4
 Qt VS Add-in 1.2.2
 Qt 5.2.0 32-bit
Steps to reproduce:
1.  Load a VS2012 project/solution that uses Qt.
2.  Open Project Properties.
3.  Go to C++->General page.
4.  Make a change to Additional Include Directories.
5.  Click Apply.  ---> hang
If the Qt VS Add-in is enabled, the VS2012 GUI will hang for a long time (a few minutes to ~1hr), depending on the size of the project. If you wait long enough, the operation finishes and you can resume using the GUI.
If the add-in is disabled (e.g. via the menu Tools->Add-in Mannager...), then there is no hang.