There are plenty good tutorials explaining how to add a section to the backoffice. But is it possible to change the existing sections (preferable without touching the Umbraco sourcecode?

For example change the color of certain items in the content tree depending on a condition.

Or making the content view editable/not editable depending on a condition.

(As you can see I want to implement a locking mechnism that locks content for users if it is edited/saved by someone else but not published yet.)

Thanks for any help.

Nils