Fix for placeholder text not being grayed out in IE10

looks like a similar issue to #5166
Table: Removed duplicate display property from CSS. Fixes #5985. Thanks @mish7 !
Theme: Use shorthand for background color fallback to make it work on IE7. Fixes #6002.

Note: The issue won't be fixed if you use ui-icon-alt. See comment at #6002 in the issue tracker.
Merge pull request #6004 from eug48/patch-1

Fix for placeholder text not being grayed out in IE10