A super simple way they could design for this is to allow a corner grab. For example, right now to expand the grid to the right or left you grab the grid on the right or the left and for expansion below or above you grab the grid at the top or the bottom. If they created a corner grab, the grid would know you only want to remove the last item in the bottom row (or the first items in the top row if you needed to remove items from the upper part of the grid).
A super simple way they could design for this is to allow a corner grab. For example, right now to expand the grid to the right or left you grab the grid on the right or the left and for expansion below or above you grab the grid at the top or the bottom. If they created a corner grab, the grid would know you only want to remove the last item in the bottom row (or the first items in the top row if you needed to remove items from the upper part of the grid).