Im new in Eclipse RCP programming but im currently learning and have got problem. I would like to know how to do some easy behaviour proper way in Eclipse without any tricks. Imagine i have got view which have got some tree. This view have toolbar buttons lets say A and B. Those buttons operate on tree and change its state. If i press button A it should change tree state and this change of tree state should also change state of B button (deactivate it). I know i can put some command expression 'activeWhen' on comman handler. But how to make it read state from tree object? Should i use some property tester? Anybody could explain me how to use property testers and how commands and handlers behave becouse there is no good explanation of that? I will be gratefull for help.
Thank you for answer and help but ive find out different way. I use sourceProvider extension for represent state of my navigation tree and then i can easy check status using eclipse expressions. This way i use eclipse functionality and dont have to bother about how to implement checking status functionality.