Get the column position from the left edge of the control's window.

Call:

ts_dialogcontrol(iDialogcontrolDescr, " GetTabFieldPosition ", int tabpos, int &begx, int &endx);


Here:

tabpos - column number (index from 1),

begx, endx - start and end in pixels from the left edge of the control's window (not to be confused with the left edge of the dialog itself).