fMoveDelta
fMoveDelta = point;
else if (fMoveDelta != BPoint(-1, -1))
if (fMoveDelta != BPoint(-1, -1)) {
fStartCorner += (point - fMoveDelta);
fEndCorner += (point - fMoveDelta);
fMoveDelta = point;
if (fMoveDelta != BPoint(-1, -1))
fMoveDelta = BPoint(-1, -1);
BPoint fMoveDelta;