Improve grid row selection UX

[rhoerr]

Suggestion: Two enhancements to row selection on grids

1. Highlight selected rows on the grid, maybe with a slight yellow color. This would make it easier to see what's selected, especially when working with multiple rows and looking at other data on the grid.

2. If you select one row, and then shift-click select another row, also check all the rows in between them. This would make it much faster to select many rows at once.