I noticed some strange behaviour with running my Eclipse 4 application on Kepler M4 platform. If the HandledMenuItems are connected to a CommandHandler, they will always show up disabled. This is not true if the application is executed with a 4.2 platform.
First I thought this is related to using Core Expression visibility rules. But it seems this is also true if I don't use them. I'm not sure why this happens and I opened a ticket for this. I even attached an example.