Create a Selective Overlay

The overlay created in Create a Publication-Specific Overlay is an inheritance overlay: it is applied using the normal template inheritance mechanism, where any top level area that isn't empty automatically overrides the corresponding top-level area in the parent template. This works perfectly well, but in some cases you may want a bit more control. In particular, you may want to override only part of a top-level area.

To create the same specialization as you created in Create a Publication-Specific Overlay using a selective overlay you would need to:

Start Content Studio and log in as a user with editor or journalist access to blueprint-one.
Find the default template (config.default) in the section tree and right-click on it.
Select Create subsection... from the displayed menu.
Fill the fields in the new template as follows:

Section unique name

Enter overlay.dailynews.config.default. The second part of the name (called the overlay key) must be the name of the publication you want to specialize. It must be an exact case-sensitive match for the publication name.

Section name

Enter a short string (one character is enough). You are required to enter a name in this field, but whatever you enter will be replaced with an automatically generated name of the following form:

<key>parent-name

where key is the name of the publication that is to make use of this overlay (i.e dailynews) and parent-name is the title of the parent template the overlay will modify (i.e Default).

Relative directory URI

You can leave this blank: it will be filled with an automatically generated name.
Save the overlay and close it.
Double-click on the new overlay in the section tree to open its section page editor.
From the menu bar, select Tools > Change layout.
In the New layout field of the displayed dialog box, select Overlay config. You will see that the template's layout now consists of a single top-level area called Overlay config area.
Right-click on the Overlay config area and select Insert > Insert new Area overlay group from the displayed menu.
Click on <untitled> and enter a name for the new group (Header Overlay, for example).
Click in the Referenced area field (in the options area on the right) and select Header.
In the section tree, double-click on the new overlay's parent template (config.default) to open its section page editor.
Select everything in config.default's Header area, right click and select Copy from the displayed menu.
Switch tabs to the overlay editor, right-click on the group you created and select Paste from the displayed menu.
Make whatever changes you require to the layout components you have pasted in to the header overlay.
Click on Publish to save and publish your changes.

An overlay created in this way does exactly the same thing as an inheritance overlay: it replaces the entire Header area of the overlay's parent template. This may not always be exactly what you want: maybe the Header area contains four or five groups, and you've only actually made a change in one of them. This unnecessary duplication increases your maintenance overhead: if you modify the header in the future, then you will probably need to modify the overlay as well to keep them synchronized.

To avoid such unnecessary duplication, you can create a selective overlay that only contains the specific group you want to modify. To do this you follow the same procedure, with the following changes:

At step 9, select Insert > Insert new Group overlay group instead of Insert > Insert new Area overlay group.
At step 11, click in the Referenced group field (in the options area on the right) and enter the name of the group you actually want to modify.
Replace steps 13 to 16 with the following:
1. Select the group you want to overlay.
2. In the group options on the right, check the Allow override option. This is an important step – if you don't do it, then you won't be able to create the overlay.
3. Right click on the group and select Copy from the displayed menu.
4. Switch tabs to the overlay editor, right-click on the group you created and select Paste from the displayed menu.
5. Make whatever changes you require to the layout components you have pasted in to the header overlay.
6. Click on Publish to save and publish your changes.