To configure check for Template -> Constants  Editor -> TX_FDFX3COLS_PI1.

If you decide to use a different marker for the height property of the the div-section you can set it

Example template for tables based rendering is EXT:fdfx_3cols/tpl.3column.html. If you want to use div based rendering select EXT:fdfx_3cols/tpl.3column.div.html. To adjust the css to your need either adjust CSSDEFAULT_STYLE or copy it to your style sheet and fix it there.