As the question/answer editor currently stands, ⌘H inserts
## Heading ##.
I often want to use the Hide shortcut while editing, so is there any way I could disable it? Otherwise, would people mind if we changed it for everyone?
I think that this shortcut collision can't be dealed with at the last coming level alone (which is here the text editor window).
If a user can't know which application, or which application level is listening to his keyboard, then this will lead to 2 kinds of problems:
This knowledge of which application and which application subwindow is obeying to the keyboard must be provided by the OS, i.e. MacOS X. If an application want to remap the cmd ⌘+H shortcut, then the system should display clearly this input control change. For example, if an embedded editor, as is the case with the StackExchange one, decide to change some shortcut (and hence the behaviour of my keyboard), I'd like to see this event displayed clearly in the upper most corner of the menu bar :
Firefox → StackExchange editor
If sufficiently many others think that this security function might be an improvment to MacOS X, the correct line of action is to feed Apple with a security improvment of UI.
In the mean time, and if this is possible at the StackExchange interface level, I'd suggest to highlight the border of the window which does have the focus and changed the keyboard mapping.