- Don't send keep-alive request when system is busy

program/js/app.js

@@ -5711,7 +5711,14 @@ function rcube_webmail()
     if (this.env.keep_alive && !this.env.framed && this.task == 'mail' && this.gui_objects.mailboxlist)
       this._int = setInterval(function(){ ref.check_for_recent(false); }, this.env.keep_alive * 1000);
     else if (this.env.keep_alive && !this.env.framed && this.task != 'login' && this.env.action != 'print')
-      this._int = setInterval(function(){ ref.http_request('keep-alive'); }, this.env.keep_alive * 1000);
+      this._int = setInterval(function(){ ref.keep_alive(); }, this.env.keep_alive * 1000);
+  };
+
+  // sends keep-alive signal
+  this.keep_alive = function()
+  {
+    if (!this.busy)
+      this.http_request('keep-alive');
   };
 
   // sends request to check for recent messages