holding directional key only moves selected node once

[dante]

when viewing a grid with a virtual scrollbar, if you select an element, then hold up or down arrow, the selection goes to the next node, though only once. keydown/keyup works as expected.

would be a minor issue, however, the virtual scrollbar continues to try to scroll the pane, and the code that keeps the selected node in the pane's viewport fires, and they battle. releasing the key stops the behavior.

[Becky Gibson]

and (quoting phiggins from dojo-meeting) "it should use typematic instead of doKeyDown because holding the arrow never moves a cell but once"

[dante]

also just noticed: holding the up arrow does not display the same behavior. the scrollbar continues to scroll, and the node is allowed to scroll out of view. It will stay out of view until the next keypress, at which point the scroll offset will snap to make the selected node in view. ff2/osx fwiw, but i suspect it is more of event logic than browser quirk.

[benschell]

I'm taking a stab at a whole bunch of Grid bugs. Re-assigning.

[benschell]

Even without the fix for #4848, I don't see this behavior. I think something changed in the key handling code in the past 3 months to make holding the up/down keys work properly. Especially with the fixes for #4848, this doesn't seem to be a bug any more. Marking as 'worksforme', please let me know if you're still seeing the behavior.