No way to do an exact text search in the comments of an RTC item?

I would like to find easily all the open RTC items that contain "On branch master:" in a comment.  It seems to me that it should be easy, but I can't seem to get what I want...

If I enter "On branch master:" without the quotes in the search box of my RTC 3.0.1.2 client, I get a list of 11 items titled Showing 11 (of 2117 work items containing 'On branch master:') - All Unresolved Work Items containing 'On branch master:'. But that's not ok as some of the return items don't have the text I'm looking for, and some items that have the text don't show up.

I tried to build a query instead of using the search field. The query for 'open items', without the condition on the 'full text', returns 1236 items. But when I add the condition that Full Text contains 'On branch master:", I get Showing 13 (of 1936 work items containing 'On branch master:'). And again some items show up that don't have the text, and some don't that have it...


I know that RTC has a fancy search mechanism that will try to help me (as referred to in e.g. this answer). But that's actually hurting me here...
Is there a way to get what I want?  That seems very basic behavior that should be available...