I would suggest checking if the src
attribute of every image is correctly constructed, as there may be scenarios, in which a non existent image file is referenced. Also, you could use the RadSlider's client method get_activeHandle()
in order to get the client object of the currently dragged handle and to utilize it for retrieving the according data.
Note that currently I am mostly guessing as to what your setup is. If you are
to resolve the issue at hand, please prepare and send a simple, runnable page
that isolates the problem so that we can examine it and provide a more to the point answer.
the Telerik team
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