"Call Stack" window in MonoDevelop crashes Unity Editor

We're running Unity 4.6.0b20. I connect our source code in MonoDevelop to the Unity Editor. When I then run the executable in-Editor, I've breakpointed in a method that, when the breakpoint is hit, has a moderately deep callstack, about ten-twelve calls deep; the method is being called ultimately from an Update method. But when I try to visualize the callstack, in the Call Stack window, within a second or so the Unity Editor will crash. MonoDevelop then obviously loses connection, but does not crash. Note that it's only the Call Stack window that causes this behavior: all the other debug windows, e.g. Watch and Immediate, are fine to display and show useful data. This is happening on multiple machines in our setup.

Is anyone else experiencing this behavior? Is there any more information I can provide to help debug this behavior?

Thanks,

Mark Barrett