fix overlay

ui.js

@@ -37,6 +37,10 @@
         this.frame.style.position = 'absolute';
 
         if (this.options.overlay) {
+            var window_size = Yeti.DOM.getWindowSize(),
+                scroll_offset = Yeti.DOM.getScrollXY()
+            ;
+
             this.overlay = document.createElement('div')
             this.overlay.style.top = 0 + 'px';
             this.overlay.style.left = 0 + 'px';
@@ -44,8 +48,8 @@
             this.overlay.style.zIndex = this.frame.zIndex - 1;
             Yeti.DOM.addClass(this.overlay, 'ui-frame-overlay');
 
-            this.overlay.style.width = document.body.scrollWidth + 'px';
-            this.overlay.style.height = document.body.scrollHeight + 'px';
+            this.overlay.style.width = window_size.width + scroll_offset.X + 'px';
+            this.overlay.style.height = window_size.height + scroll_offset.Y + 'px';
 
             Yeti.Evt.bind(this.overlay, 'click', function() {
                 _self.detach();