The main reason for experiencing this issue is the absolute positioning of the elements in the demos.
In you are using a similar approach in your project, the problem could be workarounded by attaching a handler to the window.onresize
event where to collapse()
the RadSlidingPane. This will make the RadSplitter recalculate its absolute position depending on the new window's size.
You could find more useful information in the RadSlidingPane's Client-side API
the Telerik team
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