Well, you can create layouts during runtime if that's what you're asking. If you create all of the elements in XML you can later arrange them inside of the game using code. However depending on how you go about it, you may or may not get EQ2 to save enough data about the window to save that layout correctly.
But if all you had to do was resize boxes inside of a resizable grid, I don't think you even need code for that... just pack resizers.
Scale by rows is a confusing description, is that like how the effects window fills itself with icons..?
Personally looking at that screenshot just confuses the hell out of me.
