Comment 32 for bug 909328

>> use the canvas selection callback for updating the "xx objects found" label
>Sorry not quite understanding this. Do you suggest we update the "xx objects found" label when the selection on canvas changes ? Even when the user changes the selection ?

What I intended is that when the amount of selected objects changes (because of an action of the user), the label should be blanked. Reasons:
- one or more objects that meet the selection criteria can have been deleted in the mean time. The info shown in the user interface should in my humble opinion allways be correct (which is not when an object is deleted and the label not updated)
- for complex documents, one might get confused whether the current selection is still the selection of objects that meet the selection criteria
- actually, when the user is informed on the number of objects that agree the selection criteria just after he presses the search button, it is all right: the objects are selected at this moment and this number of objects is also shown in the statusbar (along with the object type).

Therefore, I would use the desktop tracker to empty the label when the selection changes (e.g. no selection, other objects selected, etc.). Look for example in the code of the object attributes dialog for connectChanged (property of the desktop tracker) and selectChangedConn.