[e4-dev] Certain model selection events not being propagated

[Dean Roberts <Dean_Roberts@xxxxxxxxxx>]

Currently the UI model does not propagate
selected element events if the selected element is the same element that
was previously selected.  I believe that this decision is being made
too far down the model.  I believe that when modeling a presentation
layer, selection events are important even if the item being selected has
not changed.

One example is opening and closing a
fast view by clicking on its tool bar item.  In the current code base
this works, but only through a hack that has model service code injecting
directly into an add-on.  As part of work on a different defect, Eric
asked me to look at cleaning this up.

A more "correct" way to accomplish
this would be to have the TrimStack subscribe to ElementContainer SelectedElement
events.  The problem is that when the tool tips is pressed the first
time, a selection event is sent as the selection changes to the PartStack
containing the fast view tool items.  However, once open, clicking
on the tool item will NOT send an event because the PartStack being selected,
is still the same PartStack.

Similarly, while working on a fix for
(bug https://bugs.eclipse.org/bugs/show_bug.cgi?id=340875
- Opening file from minimized package explorer does not switch to  editor)
I encountered the same kind of problem exists.

By listening for selection events in
the editor area, you can minimize the package explorer fast view when a
new editor is selected.  However, if the same editor is selected no
selection event is sent.

I would argue that while MANY event
handlers won't care about selection events where the selection does not
change, it should be left up to each event handler to make this decision.
 There are valid reasons a UI presentation would care about all selection
events.

Perhaps we could make a 2nd selection
event that fires for all selections, even those where the selected item
does not change.  This would minimize the impact on existing code.

Despite the short notice, perhaps we
could talk about this on today's call.

Dean_Roberts@xxxxxxxxxx