Symptoms

Despite a default theme selected for your space, clicking on the Layout link in Space Admin reports the error "Cannot Customise Space Layout".

"You can not customise the site look and feel while a theme is active. You must first disable currently configured theme."

Cause

This is caused when the site theme (aka global theme) has been configured to use another theme. Confluence recognizes the global site theme as the default theme for the space and ignores the default theme as set within the Space being administrated. Effectively, the Global Site theme overrides the configuration of the Space default theme.

Workaround

1. Revert the Site Theme to Default Theme
2. Customise the Space Layout
3. Change the Site Theme back to some other theme

Resolution

See CONF-10208 - Getting issue details... STATUS