Selectmenu: remove Button widget CSS dependency for button element

Author: fnagel

themes/base/jquery.ui.selectmenu.css

@@ -13,5 +13,6 @@
 .ui-selectmenu-menu .ui-menu li.ui-state-disabled { padding: 0.3em 1em 0.3em 1em; }
 .ui-selectmenu-menu .ui-menu li.ui-selectmenu-optgroup { font-weight: bold; line-height: 1.5; padding: 2px 0.4em; margin: 0.5em 0 0 0; }
 .ui-selectmenu-open { display: block; }
+.ui-selectmenu-button a.ui-button { display: inline-block; overflow: hidden; position: relative; text-decoration: none; }
 .ui-selectmenu-button span.ui-icon { right: 0.5em; left: auto;  margin-top: -8px; position: absolute; top: 50%; }
 .ui-selectmenu-button span.ui-selectmenu-text { text-align: left; padding: 0.4em 2.1em 0.4em 1em; display: block; line-height: 1.4; }