I replied in the support ticket you submitted but I will update the forum as well to keep the community informed of the progress of the task.
Basically, my suggestion is to clear the browser's cache and cookies as follows:
1. In all browsers, log out fromplatform.telerik.com and telerik.com.
2. Clear the cache and your browser cookies for app.icenium.comand platform.telerik.comin all browsers.
3. Check if the issue still remains.
If this doesn't help we will need to examine the requests the InBrowser AppBuilder
client performs to the servers and see if we can find what might be preventing the 'delete' and 'create new' operations.