The following worked for me...
(1) use a suitable sequence of unit numbers for the child windows, and arrange to hold the current unit number and first and last valid unit numbers for child windows in some common block or module.
(2) use insertmenuqq to add items "first", "previous","next","last" directly on the menu bar of the main window, and construct call-back routines for each of these.
(3) in a typical call-back routine (eg. next here), increment the unit number checking it doesn't go out of range, then call the function focusqq for the new current unit number.
tHis should work either with "cascaded" child windows, or with a child window maximised within the main window.
