Doing EVERYTHING in litter tray?!

Ok, so the last 4 days Neo has been solely in his playpen due to painting his hutch, he was going to have the hutch back however the cuprinol is still tacky and now he's got to wait another day or so!

Anyway, he's got:
Litter tray
Hay manger above
Tunnel
Wooden arch
Toys
Cardboard box
Willow box

Lots of things to do but he is washing himself in the litter tray, sleeping in it, eating in it and generally chilling out in it... Why?! It's a bit gross as he's sleeping in his wee and poop. Do we think it's because it's softer (cardboard pellets in it) and therefore more comfy?

Or am I being paranoid?

Some rabbits do spend a lot od time in their litter tray. If you put hay in that kind of acts like a barrier between the wee and the rabbit. My indoor rabbits get their litter trays changed twice a day but once a day should be ok.

I wouldn't worry about it; he obviously feels safe in there, which is good. Not that he doesn't feel safe anywhere else of course, but he simply prefers his litter tray. He may move to somewhere else in time but as suggested above just put some hay or straw or something else in his litter tray so he doesn't get wet fur. My girls like to snooze in their litter tray sometimes as do most bunnies, so just let him get on with it.