Comment 53 for bug 586910

Part 2 is finished:
https://git.eclipse.org/r/#/c/50125/

Tree/Table/List now manually send the DefaultSelection after the double click event.

I also added code so that it would send it
 - After a MouseDoubleClick event
 - Space (no modifiers)
 - Shift+space (and no other modifiers)
 - Return (no modifiers
This is to preserve functionality of row-activation as per GtkDocu:
https://developer.gnome.org/gtk3/stable/GtkTreeView.html#GtkTreeView-row-activated

With these two patches double-clicking in package explorer now passes focus correctly to the editor. It also impacts all other tree-double click widgets, e.g double-clicking no a breakpoint now shifts focus to the code-line that the break-point is on. Etc..

Patches are ready for review.