diff --git a/ui/core.js b/ui/core.js
index a946d522b..35930866b 100644
--- a/ui/core.js
+++ b/ui/core.js
@@ -207,7 +207,6 @@ if ( $( "<a>" ).data( "a-b", "a" ).removeData( "a-b" ).data( "a-b" ) ) {
 // deprecated
 $.ui.ie = !!/msie [\w.]+/.exec( navigator.userAgent.toLowerCase() );
 
-$.support.selectstart = "onselectstart" in document.createElement( "div" );
 $.fn.extend({
 	focus: (function( orig ) {
 		return function( delay, fn ) {
@@ -225,12 +224,17 @@ $.fn.extend({
 		};
 	})( $.fn.focus ),
 
-	disableSelection: function() {
-		return this.bind( ( $.support.selectstart ? "selectstart" : "mousedown" ) +
-			".ui-disableSelection", function( event ) {
+	disableSelection: (function() {
+		var eventType = "onselectstart" in document.createElement( "div" ) ?
+			"selectstart" :
+			"mousedown";
+
+		return function() {
+			return this.bind( eventType + ".ui-disableSelection", function( event ) {
 				event.preventDefault();
 			});
-	},
+		};
+	})(),
 
 	enableSelection: function() {
 		return this.unbind( ".ui-disableSelection" );