Workaround IE10 problem where Dialog's close icon doesn't get focus.   Not sure why tabindex="-1" isn't working but in this case we can just set it to tabindex="0".  Fixes #16961 !strict.
Workaround IE10 problem where Dialog's close icon doesn't get focus.   Not sure why tabindex="-1" isn't working but in this case we can just set it to tabindex="0".  Fixes #16961 !strict.

git-svn-id: 674a2d6b1e32e53f607eb824547723f32280967e@31103 560b804f-0ae3-0310-86f3-f6aa0a117693

redaktor/deliteful