Da... hmmm. . Missing something here.
Trying to find, not sort, and know from the past if you type in one letter it will take you to the first one that has that letter starting... but it doesn't help in this case. As you stated its very sporadic.
Yet trying it understand what you where talking about and having no success in Layer Manager, I went to Utility, Layers, F1, and discovered and hit F9 Filters. Typed in the layer I was trying to find, it turned it on, and found where it was hiding in the list.
Vola... a wonderful work around.
Ha.. Thanks.. but still don't understand how you sort.