Customizer problem has didappeared in the meantime.
However the problem with mixed entries in header and footer remains.
For blog page calls like …blogpage/category/xyz… entries of headermenu and footermenu are displayed together in both the headermenu area and the footer area. For a direct call of the blogpage (without category) or of a single entry or any other page header and footer show correctly only the respective entries in header meu and footer.
