diff --git a/js/gdm/loginDialog.js b/js/gdm/loginDialog.js
index c6ac0301d..3d7996c4f 100644
--- a/js/gdm/loginDialog.js
+++ b/js/gdm/loginDialog.js
@@ -625,8 +625,8 @@ const LoginDialog = new Lang.Class({
     _init: function(parentActor) {
         this.parent({ shellReactive: true,
                       styleClass: 'login-dialog',
-                      parentActor: parentActor
-                    });
+                      parentActor: parentActor,
+                      shouldFade: false });
         this.connect('destroy',
                      Lang.bind(this, this._onDestroy));
         this.connect('opened',
diff --git a/js/ui/modalDialog.js b/js/ui/modalDialog.js
index cab256933..f0c934676 100644
--- a/js/ui/modalDialog.js
+++ b/js/ui/modalDialog.js
@@ -37,12 +37,13 @@ const ModalDialog = new Lang.Class({
     _init: function(params) {
         params = Params.parse(params, { shellReactive: false,
                                         styleClass: null,
-                                        parentActor: Main.uiGroup
-                                      });
+                                        parentActor: Main.uiGroup,
+                                        shouldFadeIn: true });
 
         this.state = State.CLOSED;
         this._hasModal = false;
         this._shellReactive = params.shellReactive;
+        this._shouldFadeIn = params.shouldFadeIn;
 
         this._group = new St.Widget({ visible: false,
                                       x: 0,
@@ -210,7 +211,7 @@ const ModalDialog = new Lang.Class({
         this._group.show();
         Tweener.addTween(this._group,
                          { opacity: 255,
-                           time: OPEN_AND_CLOSE_TIME,
+                           time: this._shouldFadeIn ? OPEN_AND_CLOSE_TIME : 0,
                            transition: 'easeOutQuad',
                            onComplete: Lang.bind(this,
                                function() {