How to add custom element when the table is fullscreen

Hi
By the way..I have a need now, when the table is not fullscreen , I can add a pagination for the table, but when I change to the fullscreen mode , the table’s position is fixed and cover the whole page, so I don’t know How to add the custom element to the table ,when it is fullscreen mode, example for the picture:

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20CBD72D-6FE7-4C2B-8C41-4866610CA475.png