In order to avoid this problem we suggest the following things:
1. Please set the RadPanelBar Width property to "100%". This will avoid placing the splitter scroll bar over the expand/collapse icon of the RadPanelBar items.
2. In order to show all RadPanelBar items when all of them are expanded ( including the ones at the bottom) please use the RadSplitter HeightOffset property.
In you case the value that should be equal to the header element height value.
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