Menu Background Music
It's possible to replace Minecraft's default menu background music with custom tracks or just disable the normal Vanilla music that plays in menus.
Disabling Vanilla Music
FancyMenu has multiple ways to disable Vanilla menu music. This can be useful if you plan to play other audio tracks in screens or if you just don't want music to play at all in some screens.
Globally
If you want no music in menus at all, this is the easiest way to do that.
To globally disable or replace Vanilla menu music in FancyMenu 3.9.0+, go to FancyMenu's menu bar at the top of screens and click Customization -> Global Customizations. Global Customizations can replace menu music without requiring a resource pack and without enabling customizations for every screen.
Per Screen
If you want more control over where Vanilla menus music should play, you should use the Music Controller element. This element gets added to layouts like every other element by right-clicking the editor background and then clicking on New Element -> Music Controller.
By right-clicking the element you can customize what types of music that plays in menus should be disabled (normal menu music and world music that keeps playing in screens that don't pause the game, like the Inventory screen).
Adding Custom Music
Now we can add the actual custom background music.
If you want to play the same custom music in all screens and need layout-level control, you should use a universal layout, which gets loaded in every screen that has customizations enabled. For simple global menu music replacement, use Global Customizations instead.
When using a universal layout, the music will continue playing when going from one menu with the layout enabled to another one with the same layout enabled.
If you want to play different music per screen, use normal layouts.
In this example we will use universal layouts.
Add a new Audio element to the universal layout, which will act as our background music player.
Now add music tracks to it that should play in the background.
That's basically it already.
You can also set the Audio element to shuffle mode and change its sound channel if needed.
Save the layout and leave the editor.
Enabling Customizations for All Menus
We used a universal layout in this example, because we want our background music to play in multiple screens.
Since layouts only load in screens that have customizations enabled, we need to enable them now for every screen we want our music to play.
To do that, click on Customization and enable Current Screen Customization.
Repeat this for every screen you want your custom background music to play.
And that's it! You now have custom background music in your Minecraft menus!