Button: Apply overflow: hidden in all browsers except IE 6,7 to avoid…

… expanding the size of the button from negative text indent. Fixes #7911 - Button: icon only button in dialog causes horizontal scrollbar in Opera.

(cherry picked from commit a3a5c65)

themes/base/jquery.ui.button.css

@@ -7,7 +7,7 @@
  *
  * http://docs.jquery.com/UI/Button#theming
  */
-.ui-button { display: inline-block; position: relative; padding: 0; margin-right: .1em; text-decoration: none !important; cursor: pointer; text-align: center; zoom: 1; overflow: visible; } /* the overflow property removes extra width in IE */
+.ui-button { display: inline-block; position: relative; padding: 0; margin-right: .1em; text-decoration: none !important; cursor: pointer; text-align: center; zoom: 1; overflow: hidden; *overflow: visible; } /* the overflow property removes extra width in IE */
 .ui-button-icon-only { width: 2.2em; } /* to make room for the icon, a width needs to be set here */
 button.ui-button-icon-only { width: 2.4em; } /* button elements seem to need a little more width */
 .ui-button-icons-only { width: 3.4em; }