Dialog: Attach pagebeforeshow handler using ._on(). Fixes #2215.

When a dialog widget is destroyed on an element, the pagebeforeshow handler must be removed, otherwise, if another dialog widget is instantiated on the same element later on, the handler from the previous instance will be left around and so the new instance will have the event handled twice.

js/widgets/dialog.js

@@ -17,6 +17,17 @@ $.widget( "mobile.dialog", $.mobile.widget, {
 		corners: true,
 		initSelector: ":jqmData(role='dialog')"
 	},
+
+	// Override the theme set by the page plugin on pageshow
+	_handlePageBeforeShow: function() {
+		this._isCloseable = true;
+		if ( this.options.overlayTheme ) {
+			this.element
+				.page( "removeContainerBackground" )
+				.page( "setContainerBackground", this.options.overlayTheme );
+		}
+	},
+
 	_create: function() {
 		var self = this,
 			$el = this.element,
@@ -51,15 +62,10 @@ $.widget( "mobile.dialog", $.mobile.widget, {
 		})
 		.bind( "pagehide", function( e, ui ) {
 			$( this ).find( "." + $.mobile.activeBtnClass ).not( ".ui-slider-bg" ).removeClass( $.mobile.activeBtnClass );
-		})
-		// Override the theme set by the page plugin on pageshow
-		.bind( "pagebeforeshow", function() {
-			self._isCloseable = true;
-			if ( self.options.overlayTheme ) {
-				self.element
-					.page( "removeContainerBackground" )
-					.page( "setContainerBackground", self.options.overlayTheme );
-			}
+		});
+
+		this._on( $el, {
+			pagebeforeshow: "_handlePageBeforeShow"
 		});
 
 		$.extend( this, {