Finds the next element in the 'top group' of the GUI Stack. It assumes you have already called GUIFindFirst or have in some way verified that the stack is actually open (via OpenGUIStack) and elements are on it (via PushGUIStack). This routine is useful for extracting information from input forms after the user quits a form or other GUI group.
hl = the first byte of the entry the program is currently at.
de = the first byte after the last byte of the top group.
You can use the hl and de values that were returned by GUIFindFirst or a previous call of GUIFindNext
c = 0 if there is a next item and de and hl are valid; 1 if we were already at the end and hl / de are invalid.
hl = the first byte of the size of the next element in the top group
de = the byte after the last byte of the top group.
It is recommended that you push hl and de if you plan to use GUIFindNext again; that routine requires the data of these two outputs as inputs.
GUIFindNext([hl],[de]) - To specify non-register values
GUIFindNext() - To use already-set contents of hl and de
a, bc, de, hl, Op1