Finds the ath non-groupmaster element in the 'top group' of the GUI Stack. In other words, it actually returns the second or later item in the group, after the GUIRSmallWin, GUIRLargeWin, or GUIRnull item. Unlike GUIFindFirst and GUIFindNext, assumes there is an open GUI stack. This routine is useful for extracting information from input forms after the user quits a form or other GUI group.
a = number of items to skip before returning an item
hl = the first byte of the size of the first element in the top group
de = the byte after the last byte of the top group.
bc = size of the current element
It is recommended that you push hl and de if you plan to use GUIFindNext; that routine requires the data of these two outputs as inputs.
a, bc, de, hl, Op1