This code in Resize method make it works:

*!* Work around the bug with minimizing modal form
IF this.windowstate # 1 && if this window is minimized
FOR EACH oForm IN _SCREEN.Forms && loop through all the formas
IF oForm.WindowType = 1 && if found modal form
lcModalForm= oForm.Name && name of modal form
WITH &lcModalForm
.windowstate = 2 && Maximize modal form
.windowstate = 0 && put modal form in normal size
ENDWITH
ENDIF
ENDFOR
ENDIF