NodeGraph : Avoid confusing box navigation

[johnhaddon]

Previously we would happily dive down into any box, even if it was totally unrelated to the current root, or several nesting levels deep. We now only jump if the new root is a descendant of the current root, and if it is nested several levels deep we step towards it one level at a time.

Fixes #2343

[dbr]

Ah, yes, this is a much neater approach than alternating the global selection.

I think the only place where #2344 wins is there is a visual indication of which box will be opened (whereas with this approach the highlighted node will be buried in the nested group somewhere). Perhaps when a node is selected, all the parent boxes would be "partially highlighted" (something like a stripped highlight or only-node-border highlight or something like that)

[johnhaddon]

I think the only place where #2344 wins is there is a visual indication of which box will be opened (whereas with this approach the highlighted node will be buried in the nested group somewhere)

Good point. I did originally start with an even simpler approach - only diving into the selected box if it was parented to the current root. This meant there was always a visual indication of where you were going, at the expense of an Up/Up/Down/Down sequence not taking you back into the most nested box. Instead, after popping up two levels, you would need to reselect the outer box to go back down. If that doesn't seem like too much of a drawback, I'd happily update the PR with the simpler version.

Perhaps when a node is selected, all the parent boxes would be "partially highlighted" (something like a stripped highlight or only-node-border highlight or something like that)

That doesn't seem like an unreasonable suggestion, but it doesn't seem high enough priority that we'd get to it any time soon...

[johnhaddon]

I did originally start with an even simpler approach - only diving into the selected box if it was parented to the current root. This meant there was always a visual indication of where you were going, at the expense of an Up/Up/Down/Down sequence not taking you back into the most nested box. Instead, after popping up two levels, you would need to reselect the outer box to go back down. If that doesn't seem like too much of a drawback, I'd happily update the PR with the simpler version.

I've added a second commit which goes back to this original approach. The first commit is still there as a record of the more complex approach should we decide that is preferable after all. I'll merge this once the tests pass.