Somewhat covered in this, but doesn't really get into panels...

http://blog.arvixe.com/styling-drop-down-menus-in-Composr-part-1/
http://blog.arvixe.com/styling-drop-down-menus-in-Composr-part-2/

User can make changes to the “panel_top” of a theme using Composr. You need to go to the CMS Zone, then Pages (Comcode pages) and select “panel_top” page from the list to customize it.

For example:
(image_001.png)

Press the “Edit” button. Then, you can write anything in the editor which needs to be displayed on the “panel_top”. We can also include comcodes in the text content.

For example:

It is currently {$TIME}.{+START,IF,{$NOT,{$IS_GUEST}}} You are logged in as {$USERNAME}.{+END}

(image_002.png)

Example explained:
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{$TIME} is a pre-defined comcode which is used to display the current time.
It checks whether the user is a guest (not logged in) or a member (logged in) using the comcode {$IS_GUEST}. And it displays the message “You are logged in as {$USERNAME}” only when the user is a member of the site. The comcode {$USERNAME} is used to fetch the username of the user.

The user can watch the preview before saving the changes by pressing the “Preview” button in the bottom of the page. Preview of the given example is shown below:

(image_003.png)

Save the changes by pressing the “Save” button. Those changes will be applied to the site. User can see the changes in website's home page.

(image_004.png)

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Haven't used this, as it is just repeating core concepts. However I have taken it as a cue that the structure tutorial should go into much more detail as to what exact panels may exist, what the defaults do, etc. Also the guest detection example is now used in the Tempcode programming tutorial.