[pblankenbaker]

In navigating through the source, it does not look like it is possible (at least not easily) to unregister a button handler.

Could you work around this by refactoring your command to take into account the SOME_CONDITION? For example if the difference is only in your execute() method, could you change your command implementation to:

protected void execute() {
   if (SOME_CONDITION) {
      executeCondition();
   } else {
      executeNormal();
   }
}