Inspector pane selector can easily be smarter

[Ducasse]

Right now the user is always forced to reclick on a pane to see it when this pane is different from the source. Presenting the same pane as the source one is good WHEN the resulting pane is not already open. Now when the resulting pane is already open, clicking on a source element should NOT change the kind of pane is open. Else the user has to constantly and systematically reclick to see its result ;( :(