Is it possible to display sub menus but the arrangement is alphabetically?
Not automatically -- the menu uses the Asset Map order to display child items (so that you have complete control over the ordering). There is an Asset Sorting tool in the Tools menu that can sort your assets alphabetically, but you would need to run this manually.
We have quoted a client on creating a trigger action that automatically sorts children, but they have not approved that development yet.
Yes that would be useful if it has a trigger. Thanks 