You may want to disable inline module editing, i.e because you don’t want the logo in the HTML module to be editable, as there is a link on the logo that leads back to the homepage.
If you want to disable inline editing you can add a 'noEdit' class to your custom HTML module.
- This is done by clicking "System" in the menu then navigating to 'Manage' > clicking on 'site modules' > searching for your module (in this instance ‘logo’) > selecting the 'Advanced' tab and adding to ‘Header Class’ > ‘noEdit’.