Hi billberet,
While the look of the Buttons/images/other items on the main menu page is handled under "skin editor", you need to go into Alt-F2 (setup) to get the buttons to behave the way you want.
The right items on the menu page in the default skin are displayed (and hidden) using an "ID" tag (I'll explain how this is done in the second part of my post.)
First Part:
If all you want to do is add more covers or other pics of a particular type, just open skin editor when the items you want more of are visible, and copy and paste more until you get the look you want - static images will be copies, and database items like media covers and pics will be random, and you can resize them all as you like. You can also add text, shapes, or other elements, as long as they have the proper "ID".
Second Part: (Warning: Long description)
If you want to create new menu items, or want to add other elements like text descriptions to the right side of the main menu, it helps to understand some of the main menu's built-in functionality, as well as to have a basic understanding of the "ID" textbox in "Element Properties" (It seems to me, from reading several of your posts, that you are pretty comfortable with skinning, and setup, so here goes).
ID textbox: (This one's pretty straight-forward - almost too simlpe.)
What the ID textbox does (AFAIK) is just assign an "ID tag" to that element - and you don't have to do any other programming to assign an "ID tag" just type the name in the box, and your done - straight-forward right?
Although some "ID tags" are "reserved" (Like: "nowplaying>music") you can pretty much use whatever tag you want - just remember that if you use a tag that is "reserved" or referenced elsewhere in your skin, the behavior of your item will likely be affected.
Once an item has an "ID", you can modify the behavior of that item by creating events events that do something like show or hide any button that has that "ID tag". Assuming you already know how to create an event, you can now use events to do things like hide and show your "ID Tagged" items. (eg. Event Group: xlobby, Commands: button hide, and button show - when you drag the command over to each event, remember to type in the "ID" in the textbox)
The main menu page category/supplemental items "behavior" is created by the interaction of the two main "components":
Component 1 is the group of "scrolling" menu images with text description (that's the "category").
Component 2 is the group of "supplemental" images and collages (the covers or other artwork that are displayed on the right side).
If you open the skin editor and click on one of the covers or other artwork, you can find that item's "ID tag" in the "ID" box in skin editor under Element Properties\General.
Remember that the main menu is a "special" category, the behavior of which is modified in Alt-F2 Setup in the Databases tab (Not in the "skin editor"). The main menu category is special in that, among other things, you do not have to "create" the show/hide events for the items on the right. To add a new element to the main menu, and have it work like the rest of the main menu elements, there are a few steps you'll have to take (it doesn't really matter which step you do first, but I prefer to create buttons or other items with "IDs" before I create events that call those "IDs") some screenshots of the steps along with the finished menu item and sample images and text descriptions are included for reference.
The two steps to accomplish this are 1, create the supporting images or text descriptions on the right side of the menu screen, and enter their "ID tags"(use the same "ID Tag" for each button that you want to be controlled by a particular menu item, and you will have to enter one "ID tag" later to control the behavior of all the buttons/images/text descriptions), and 2, add/create the menu item in the main menu "category".
Once you have created the images/text descriptions, or other items on the right side of the main menu screen, you are ready to create a new main menu category.
-In Alt-F2 under Databases\Manage: highlight "menu", and click on Database Actions\"edit".
-DB Editor will open, and you'll click the "add new item" button. This will add "new item" to the bottom of the menu database.
-Highlight "new item" and change the name in the "Display:" textbox on the right under the "Default" tab. ("I used my new menu item")
-to enable the ability to check/uncheck whether this item is displayed, add the field "visible" to this item by typing "visible" in the "add field" textbox at the bottom of the DB Editor window, and click "add field"
-once "visible" is displayed in the "fields" column (under the "Remove Field" button), you can add a value for the field you just created.
-the field "visible" should now be highlighted, and you should now type "true" in the large textbox to the right of the "Remove Field" button.
-now it's time to add a primary image to your menu item, so that it will match the rest of the menu items in the main menu category.
-you can type in the location of the image you want to use in the textbox under the word "Coverart:",
-or you can "Browse" to find the Coverart you want to use.
-The "Move To Item Folder" does not work for menu coverart on my current build, but it does work for movies and music covers.
-Next, click the "Advanced" tab in DB Editor and Add an event to your database item.
(make sure your database item is still highlighted, or you will not be able to add an event. I used "goto:goto my new menu item's page" in the example.)
-Last, you can now enter the "ID tags" for each of the items you'd like displayed whenever your new menu item is the highlighted menu item.
Here's the finished new menu item:
Sorry if I missed some steps, but it is late. If I forgot something, just ask, and I'll try to clarify with an edit.
Hope that helps,
Samson