Master detail how to reduce upper space in detail grid?

how to reduce space between detail and its upper frame? plz see pic

There are no picture attached

But normally you can fix that by adjusting the theme CSS

This look likes the header of the detail grid.

You can turn it off 3 ways

1- In grid property of the detail definition, set Display Header to No
image

2- In the Header & Footer Layout of the detail grid, set Display Header to off
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3- Use the macro sc_head_hide(“det”) in onScriptInit of the detail grid