XPGetWidgetGeometry
WIDGET_API void XPGetWidgetGeometry(
XPWidgetID inWidget,
int * outLeft, /* Can be NULL */
int * outTop, /* Can be NULL */
int * outRight, /* Can be NULL */
int * outBottom); /* Can be NULL */
This routine returns the bounding box of a widget in global coordinates. Pass NULL for any parameter you are not interested in.