Created attachment 391546 [details]
Stack trace from crash when opening Default Policies

User-Agent:       Mozilla/5.0 (X11; U; Linux x86_64; en-US) AppleWebKit/534.8 SUSE/7.0.528.0 (KHTML, like Gecko) Chrome/7.0.528.0 Safari/534.8

When trying to view the "Default Policies" dialog, MonoDevelop will sometimes crash with a failed assertion from the tree. I've added in a quick bit of logging just as it enters the method and whether it crashes or not seems to depend on what the item is that it thinks should be selected. If section label is ".NET Naming Policies" then it will crash, but if it is "Source Code" or other sections then it works fine. Sometimes opening the Preferences before the Default Policies seems to fix it, but that could just be coincidence.

Reproducible: Sometimes

Steps to Reproduce:
1. Start the latest MD
2. Edit > Default Policies
Actual Results:  
MonoDevelop sometimes crashes because of a failed assertion:

(G_NODE (iter->user_data)->parent != NULL)

Expected Results:  
Default Policies are shown