First I apologize for the delay in responding to your problem.
The behavior you describe is not the normal behavior for Visual Studio. Normally the test immediately starts execution when you click "Debug Selection" from Test View and then it will stop when it hits the breakpoint in your coded step. At least that's the way it has always worked for me.
Does the test appear to be running prior to hitting F5 the first time, or does it appear paused somewhere? It almost sounds like you are hitting another earlier breakpoint before the one you set in your code behind. Is it possible there's another breakpoint set somewhere else? You can view the list of breakpoints via Debug -> Windows -> Breakpoints.
If there are no other breakpoints set and you are still experiencing this problem I'd like to look at this problem on your computer via GoToMeeting. Let me know what time zone you are in and your availability and I'll setup the meeting. I'm in Austin, TX which is Central Time (GMT -6).
the Telerik team