Can't assign some apps to a desktop .. what's wrong? Usually, when I right-click on an app in the dock, I can assign it to a specific desktop/space. However, there are some apps where I don't have this option. (I've noticed it for CrashPlan and Paintcode.) 

What's wrong? 

Is there some config option on my Mac for that or is it something that the App developers have to do to enable this?
It seems like a bug in Mountain Lion. Removing the app from dock and adding it again usually resolves the problem for me.