Thank you for getting back to me.
Let me explain in more details. The version of the controls that you are upgrading from is quite different compared to the latest one. Thus, the differences in the behavior, appearance and functionality of the controls.
The behavior that you encounter with the RadUpload control - a pop up showing on click of the input - is intended by design and the scenario that you are trying to accomplish (a dialog popup to open only on click of the button) is not supported.
However, I noticed that you mention that a file selection dialog opens even if you click away from both the button and the input, if this is the case, then this is not the expected (normal) behavior of the control. Thus, I would kindly ask you for either a live url or a simplified runnable project that we can explore locally and help you out with the issue.
All the best,
the Telerik team
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