When you select the "Unlod modules" in the module, you have no result message: user can't know if modules were really unloaded or not.
You can see the situation with a sequence that load a .DLL extension is opened and has run: if you want to delete (or update) the DLL file windows prevent you to do. Make Unload, Windows sometimes still prevent you.
I've not found the real conditions to reproduce the situation but I think you should improve the user information with that Unload Modules function to shos, as ex, which modules have been really unloaded and which ones not.
I'm declining this idea due to lack of community support. Also, the Execution Profiler can be used to see Module Load/Unload behavior.