fix(dialog): fix overlay not covering, dialog position in overlay

references #908

closes #1287

src/components/backdrop/backdrop-theme.scss

@@ -1,4 +1,3 @@
 md-backdrop.md-opaque.md-THEME_NAME-theme {
   background-color: '{{foreground-4-0.5}}';
-  position: absolute
 }

src/components/dialog/dialog.js

@@ -329,13 +329,15 @@ function MdDialogProvider($$interimElementProvider) {
       configureAria(element.find('md-dialog'));
 
       if (options.hasBackdrop) {
+        var parentOffset = options.parent.prop('scrollTop');
         options.backdrop = angular.element('<md-backdrop class="md-dialog-backdrop md-opaque">');
         $mdTheming.inherit(options.backdrop, options.parent);
         $animate.enter(options.backdrop, options.parent);
+        element.css('top', parentOffset +'px');
       }
 
       if (options.disableParentScroll) {
-        options.oldOverflowStyle = options.parent.css('overflow');
+        options.lastOverflow = options.parent.css('overflow');
         options.parent.css('overflow', 'hidden');
       }
 
@@ -387,8 +389,8 @@ function MdDialogProvider($$interimElementProvider) {
         $animate.leave(options.backdrop);
       }
       if (options.disableParentScroll) {
-        options.parent.css('overflow', options.oldOverflowStyle);
-        $document[0].removeEventListener('scroll', options.captureScroll, true);
+        options.parent.css('overflow', options.lastOverflow);
+        delete options.lastOverflow;
       }
       if (options.escapeToClose) {
         $rootElement.off('keyup', options.rootElementKeyupCallback);

src/components/dialog/dialog.scss

@@ -3,10 +3,10 @@
   justify-content: center;
   align-items: center;
   position: absolute;
-  left: 0;
   top: 0;
-  right: 0;
-  bottom: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
   z-index: $z-index-dialog;
 }