Turning on the Publishing feature in a Team site  will automatically redirect
that site to use the default.master file stored in the master page gallery
of the top level site instead of its own. When the Publishing feature is
later turned off the site will still be pointing at that default.master
instead of the one in its own master page gallery. If the default.master in
the top level site was modified that may be where the 'extra blue space' is
coming from. To get it back to normal you may need to change the site back
to using the local default.master as its master page. That requires either
SharePoint Designer or custom code.



To do it in SPD:



1. Open the site and browse to the master page gallery
"_catalog/masterpages"

2. Right click on default.master and select "Set as Default Master".



If that doesn't work, then either the local master page has been edited or
something else has been done to default.aspx.