Dialog does not resize enough in height when using two resizeable listboxes

I created for my script a dialog with two listboxes. The first listbox can grow in height and width. Below is a second listbox which can grow in height and width and shall move in Y.

If you resize the dialog in Y the dialog does only scale accordingly to the height increase of the first listbox, but ignores the movement (or height increase) of the second one.
I assume both listboxes grow in Y accordingly to the height change of the dialog? And it would be necessary to split up the height increase of the dialog two both listboxes.

Picture before rezising:

After Resizing:

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Extract V2.dcf (37.9 KB)