fLeftTopOffset
fLeftTopOffset = boundingBox.LeftTop();
return fLeftTopOffset;
IntPoint fLeftTopOffset;
fLeftTopOffset = where - windowFrame.LeftTop();
float left = rintf((where.x - workspaceFrame.left - fLeftTopOffset.x)
float top = rintf((where.y - workspaceFrame.top - fLeftTopOffset.y)
BPoint fLeftTopOffset;