why can't organise brushes in custom pallet

So I love that I can create custom pallets for favourite brushes but they never seem to go where I want them.  

I can place them in the pallet but I can not place them one under the other.  Why?

if I try to move them they just go where ever they want and sometimes just disappear altogether.  And all I seem to be able to do is make the icons small or big.

why can't I organise them more easy in a stack that I like????   I've had this issue in all versions of painter I have owned.  Am I missing something?