fix stuck loading tip

customize.dist/main.css

@@ -387,6 +387,8 @@
   left: 0;
   right: 0;
   text-align: center;
+  transition: opacity 750ms;
+  transition-delay: 3000ms;
 }
 @media screen and (max-height: 600px) {
   .cp #loadingTip {

customize.dist/src/less/loading.less

@@ -36,6 +36,9 @@
     left: 0;
     right: 0;
     text-align: center;
+
+    transition: opacity 750ms;
+    transition-delay: 3000ms;
     @media screen and (max-height: @media-medium-screen) {
         display: none;
     }

www/common/common-interface.js

@@ -194,10 +194,11 @@ define([
     };
     UI.removeLoadingScreen = function (cb) {
         $('#' + LOADING).fadeOut(750, cb);
-        $('#loadingTip').css('top', '');
-        window.setTimeout(function () {
-            $('#loadingTip').fadeOut(750);
-        }, 3000);
+        $('#loadingTip').css('top', '')
+        // loading.less sets transition-delay: $wait-time
+        // and               transition: opacity $fadeout-time
+            .css('opacity', 0);
+        // jquery.fadeout can get stuck
     };
     UI.errorLoadingScreen = function (error, transparent) {
         if (!$('#' + LOADING).is(':visible')) { UI.addLoadingScreen(undefined, true); }