form and its objects communication

[wysota]

Don't check the status of the listbox in mouse events of another widget. Use signals and slots to connect to changes in the listbox's state (i.e. signals emitted by its QItemSelectionModel) to set a flag in your scene that the listbox has an item selected or not. Then just check this flag in the event. Same goes for updating the status bar - emit a signal from your scene with the new coordinates and connect it to a slot in your widget where you will update the status bar.

[eva2002]

I get it that I can use signals and slots to do the trick. The problem here is disp can see the mapscene (custom graphicsScene) object and therefore it can use the signals produce by that object. I have use this to update the position of the mouse.

However, since no reference of disp in mapscene, I can't see the signals emited by disp and hence wasn't able to reference to the signal from disp to notify mapscene that an item in the listbox is selected. This is the problem I am facing now.

[wysota]

What is "disp"? If that's an object of some kind then the answer is that you need to connect signals and slots from an object that sees both the source and target objects (which is most often the first common ancestor object of the two objects in question). If there is no such object then you can always relay (propagate) signals to the environment until a situation I described occurs.

[eva2002]

I manage to get it through by using pointers. Thanks for your help.