OK. I think I may be doing something wrong but here goes.
All my folders that contains only 1 movie are like this:

The template I used for this is the Buhric - CoverTrickle - Parent Folder
None of those will trickle. As a matter of fact, 10000 BC is the very thumb I see on my TV with none to the left of it and 9 to is right. Before 10000 BC I have 9 other movies but none show as thumbs. Even if I show the sheet for 88 Minutes

The thumb in first place is still 10000 BC.
All those thumbs are placed as yours are in a trickle position but won't trickle.
I am set to STD for my sheets and I am viewing as Thumbs. If I use Thumbgen default sheet, I see the folder sheet and if I enter the folder I see the movie sheet. No thumbs at the bottom.
Using Buhric - CoverTrickle - Parent Folder with the same view (thumb) and still in STD mode for my sheet. I see the thumbs at the bottom that should trickle but won't.
Here is one that work from inside the parent's parent. It is under the main name "Jurassic Park Trilogy" When I enter the main folder "Jurassic Park Trilogy" I see this
[img]"Jurassic%20Park%20Trilogy"[/img]
These 3 movies, when viewed on my WDTV Live will, will trickle inside that main folder. I will see the Folder Sheet for Jurassic Park II and the appropriate thumb for that movie will be in the correct location.

If I am missing some info I will try to fill it as required. I think I should have everything covered.