This function lets you lock the text on a Topic so other Map users cannot alter it.
By default a locked Topic is assigned a small padlock icon within the Topic but this can be removed by simply selecting the icon and hitting Delete if you wish to. The function operates like a toggle so if a Topic is locked and the menu button is clicked the Topic text will become unlocked and vice versa.
When another Map user tries to edit the Topic text MindManager alerts them to the fact that the current Topic is read only.
Although a user could simply delete the Topic to get around this, it is meant as a simple method of protection. Where it can be quite powerful is if you protect the text on the Central Topic. If you added a copyright/ownership statement for example because the Central Topic cannot be deleted this gives it more scope.
A later version is being developed which will also allow a password to be used to stop other map readers with the addin being able to turn the protection off.