The issue with the memory tool window will be fixed with the next rev of the hot fix.
Your other issue -- I suspected that it was related to some new code we put in to prevent the user from trying to modify a variable while the debuggee was running. However, after testing things seem to work fine, and the change in question went in after 13.0.0, so that can't be the problem you were seeing anyway. If, after applying the hot fix, you still can not modify the variable while the application is suspended, then please take note (by looking at the state of "Debug > Suspend") whether you *really* have the application suspended when you try to modify that variable.