Steps to reproduce :
1) Make sure the platforms (such as blackberry) are not configured in the preferences.
2) Open TiApp.xml and select blackberry, and then save tiapp.
3) Agree to the prompt to install the unconfigured platforms and hide it.
Once the hide button is pressed, the UI is locked up and does not allow for any UI interactions with a busy cursor. The jstack log indicates that the UI thread has been waiting for the Wizard to close or may be, for any user action on the Wizard.