The actions defined for ChooseDialogs don't support availability configuration.

This leads to the situations (for example):

• editors can choose any node when picking content, ie they can pick folders when they should be picking images, etc...
• editors can initiate an upload even though they don't have write permission in the selected folder, resulting in an exception

Please change this:
1) ChooseDialog actions should support availability rules just like regular actions in the actionBar.
2) IMHO the action buttons should not disappear, but rather just be disabled, otherwise I think the user will be confused.