by Stuart Morris
Suppose you have a combo-box widget (named combo-box-1) and you want to drop down its built-in selection-list on some event. The following source will do just that.
{windows.i} &GLOBAL-DEFINE CB_SHOWDROPDOWN 335 DEFINE VARIABLE retval AS INTEGER NO-UNDO. RUN SendMessage{&A} IN hpApi (INPUT COMBO-BOX-1:HWND, {&CB_SHOWDROPDOWN}, 1, /* True */ 0, OUTPUT retval ) NO-ERROR /* Stop C Stack Errors */.