grouping by field causes all tooltips to disappear except for last-rendered item in group

I almost gave this high priority...

If you create a view, set tooltips for that view, then set "grouping field" to anything, then all the tooltips for the features will disappear, except for the last-rendered feature in the selected group.

For example, I had tooltips displaying correctly for my view. Then I started grouping by nid (separate layer for each feature, don't ask) -- then the only feature that shows a tooltip is the the last nid to be rendered. Or, when I group by node type, then the only feature that shows is the last node type to be rendered.