Hi Nick,
> I think others , ie Felix & Minko, have also hinted at
4a & 4b not to be
> used in a style - if one is creating an overview map .
yes, I've added a check for this in --check-styles
> I see 4b functioning as an essential 'container' holding
the various 4a
> polygons together ( its often used in NT maps to
represent the sea/ocean).
> Interestingly, the error message caused by the 'locked
flag,' is less
> severe when adding a 4b polygon.
Please try r2627, this adds now the 4a background polygon.
Gerd