Selection History

[AnniekStok]

Some useful node selection controls are currently missing or not easily accessible.

Currently we can do the following:

• single click to select a node
• shift-click to append to selection
• ctrl/cmd-click to center a node
  and we have some buttons in the groups tab:
• deselect everything
• invert selection
• restore selection
• jump to next selected node
• jump to previous selected node

We currently do not distinguish between different mouse button clicks, and only check for accompanying key strokes, so we could use assign some functions to specific mouse buttons.

Missing functionalities that I would like to add (which should work both on the viewer and on the tree view):

• a shortcut for 'deselect'. This could be clicking on the background (this currently works for points but not for labels or tree view), or via the right mouse button, which might be slightly 'safer' as one might click on the viewer or the tree view just to put it in 'focus', not to deselect.
• key bindings for moving to the next (N) or previous (P) selected node.
• mouse bindings for previous selection (instead of restore selection) and next selection. I don't think we need to keep a long history, just the previous state, and the option to 'undo' restore selection by going forward again. I have a forward and back button on my mouse that I would like to use for that, but we can also have key bindings since those buttons are not present on every mouse.

[cmalinmayor]

• I like right mouse to deselect
• key bindings for next and previous yes agree
• This one is more complex. next and previous selection might not be enough to fix the problem, although it's a fine start. We also discussed maybe using the table of individual nodes to track this somehow.

A PR each for the first 2 should be quick. More iterations needed for the third idea, but feel free to make a previous/next selection functionality first and then see if theres a better way after. Whatever you find helpful!

[AnniekStok]

I realized the right mouse button is occupied on the tree view to reset the view, so I put deselect on 'Escape', but we can also choose to change the tree view settings of course.

[cmalinmayor]

We can do the same thing we do with the action history but with the Selection history. I would probably replace the current SelectionList with a SelectionHistory, so that all these helper functions operate on the History, and the actual list is just a plain list inside the history (without a class).