If you wish to protect a file from further changes, you can opt to make it read-only from directly within your workspace. This can be useful when the contents of a file do not need further changes and you need to guard against it being accidentally updated, or if you wish to formally record the version of a file as being "final", for example.
Locking a file
To lock a file, select it by clicking anywhere on the relevant row in the file list other than the file name or icon, and click the 'Lock' button on the right-hand sidebar.
A pop-up will appear requiring you to enter a comment regarding why you are locking the file. This can provide a useful explanatory note for your colleagues. Now click the 'Lock' button in the pop-up and the file becomes read-only.
Once the file has been locked, a padlock icon will be displayed on the file's icon in the file list.
The workspace activity log will also be updated showing that you locked the file, along with the comment that you entered when doing so.

Unlocking a file
To unlock a file, select it by clicking anywhere on the relevant row in the file list other than the file name or icon, and click the 'Unlock' button on the sidebar. Again, you will be required to enter a comment in support of unlocking the file. Now click the 'Unlock' button in the pop-up and the file becomes editable once more.
The workspace activity stream will be updated to show that you've unlocked the file, and display the comment that you recorded while doing so.