Ability to disable dropdown without destroy it.

src/definitions/modules/dropdown.js

@@ -219,7 +219,7 @@ $.fn.dropdown = function(parameters) {
             ? callback
             : function(){}
           ;
-          if( !module.is.active() && !module.is.allFiltered() ) {
+          if( module.can.show() && !module.is.active() && !module.is.allFiltered() ) {
             module.debug('Showing dropdown');
             module.animate.show(function() {
               if( module.can.click() ) {
@@ -1635,4 +1635,4 @@ $.extend( $.easing, {
 });
 
 
-})( jQuery, window , document );
+})( jQuery, window , document );

src/definitions/modules/dropdown.less

@@ -439,6 +439,16 @@ select.ui.dropdown {
   box-shadow: @selectionHoverBoxShadow;
 }
 
+/* Disabled */
+.ui.selection.dropdown.disabled,
+.ui.selection.dropdown.disabled:hover {
+  cursor: default;
+  box-shadow: none;
+  color: @selectionTextColor;
+  border: @selectionBorder;
+  opacity: 0.3 !important;
+}
+
 /* Visible Hover */
 .ui.selection.visible.dropdown:hover {
   border-color: @selectionVisibleHoverBorderColor;