Fix broken show in pager button

Clicking the little "show pager" button on the tooltip no longer causes the pager to be opened -- seems that the tooltip was expecting a slightly different object than it was getting. This pull request fixes that.

I was going to add tests, too, but I couldn't get it to trigger the shift-tab keypress appropriately. I might try again later to see if I can get it to work.

Fixes #6506