"Select intersection" modifier key for click-drags over row/column labels

[Robert Leach]

When the user has selected a series of entire columns and then wants to select rows to limit the selection to the resulting intersection, they currently have to do that by using option-click-drag to deselect the ones they don't want. Instead, I think it would be convenient to have a modifier combo that selects the intersection (or put another way, "deselects everything else"). Control would be a good key for this.

This would mean that contextual menus (currently using control-click) would either have to be a right-click or would have to be able to distinguish between clicks & drags.

[Robert Leach]

Example use case:

1. Select a series of columns by click & drag over the column labels
2. Hold the modifier key (e.g. control) and click & drag over row labels

The resulting selection should be the intersection of the 2 selections.

[Robert Leach]

Duplicate of #340.

[Robert Leach]

Removing milestone: Navigation (automated comment)