When scrolling with static headers are enabled grid ScrollHeight property(the height of the control's scrollable area) is set to 300px by default. This fixed height does not allow the grid to auto resize, when the data can not fill the scroll height. However, you can use the client-side GridCreated
event to check whether the table height is less than the value of the ClientSettings.Scrolling.ScrollHeight
property, and if so, explicitly modify the scroll area height to match the height of the data items as shown in the following article:
I hope this information helps to understand why this happens.
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