avoid neverending spinning wheel ui mask, when operation is stalled

src/af.ui.js

@@ -116,6 +116,7 @@
     AFUi.prototype = {
         init:false,
         showLoading: true,
+        showingMask: false,
         loadingText: "Loading Content",
         remotePages: {},
         history: [],
@@ -602,6 +603,15 @@
             if (!text) text = this.loadingText || "";
             $.query("#afui_mask>h1").html(text);
             $.query("#afui_mask").show();
+            this.showingMask = true;
+
+            var self = this;
+            //set another timeout to auto-hide the mask if something goes wrong after 15 secs
+            setTimeout(function() {
+                 if(self.showingMask) {
+                    self.hideMask();
+                 }
+            }, 15000);
         },
         /**
          * Hide the loading mask
@@ -612,6 +622,7 @@
          */
         hideMask: function() {
             $.query("#afui_mask").hide();
+            this.showingMask = false;
         },
         /**
          * @api private