Decoration tab logic?

Does anyone have any clue how the game decides what tab it puts a decoration into when removed from the ho?

I got 10 random tabs now that my ho's merged.
I keep placing them and deleting them to compress them into fewer tabs,
but I can't figure out the logic behind it.

It does not put them in the first tab/first empty slots, that's for sure.
What the hell...?

And why can't we even move the decorations around in the tab and arrange them?

We can shift+click as in split the stack, but nothing happens... I don't even wtf is this... who created this monster of a ui ??

I'd like to get some kind of feature where we could just organize those tabs and also the MTX tabs.. I mean I can't see why we wouldn't be able to do so.. so I'll just wait patiently. I also have no idea how the tabs sort the items.. o.O We want order! wooh