Hi! I use RadAsyncUpload in aspx page with RadWindow! And it doesn't visible in FireFox! In Chrome and IE it visible but in FireFox not! Help please! Thankue!)))
Its a known issue when Silverlight module is used.As a workaround try using the IFrame module to upload files with RadAsyncUpload control.Check the following help article to configure your web.config. Uploading Large Files
Here is a sample code how to disable Flash and Silverlight modules: