Inserts an interface element at the end of a list in hbox, vbox, zbox or menu.
Ihandle* IupAppend(Ihandle *box, Ihandle *element); [in C] IupAppend(box, element: iuplua_tag) -> (box: iuplua_tag) [in IupLua3] iup.Append(box, element: iuplua_tag) -> (box: iuplua_tag) [in IupLua5]
box: Identifier of an hbox, vbox, zbox or menu.
element: Identifier of the element to be inserted in the box.
This function returns box if the interface element was successfully inserted. Otherwise, NULL (nil in Lua) is returned.
This function must be used when the interface elements that will compose an hbox, vbox, zbox or menu are not known a priori (in the program's compilation stage).
If the box where the interface element is being inserted is visible, the IupAppend function does not update it automatically. For such, the box must be hidden (IupHide) and made visible (IupShow) again.
ATTENTION: Currently, this function only works before the element is mapped by means of functions IupMap, IupShow, IupShowXY or IupPopup.