ok, thanks. Right now the couple I have using the tree pick twice a day each for 4 picks a day. I know about the time slot 1-3 for yellow and I keep the tree in view at night. I tried to reset the tree using TCE but I only got the object/delete option - no reset. I assume that means the tree isn't stuck. So hopefully, the yellow will occur again of it's own accord. I'll try picking fruit around 10.00pm.
later - Yeah...I picked the fruit at 10.30pm and I got the yellow crystals. My sim got photography this time. The next night I got it again and got riding. So maybe it's a mishmash of all the skills.
I think on the whole, this tree is really a novel thing, but I probably won't use it to much. I feel it takes away an essential part of the game. I like the old fashion "we learn by doing" and "studying" approach. Well deserved credit. There are a couple subjects I really dislike and I may use the tree for those once they've achieved their other required subjects. It makes a great ornament though.
Bear