Okay so I’m used to using older versions of retroarch and mame and I got the hang of sorting out controls/controllers and quitting from games back to frontend etc.
But over the last two days I decided to update to the latest 0.195 romset and use the latest version of Retroarch with the latest MAME core as opposed to the older MAME2003 that I’m used to. So here is my problem: I press select and start on my xbox controller as I’ve always done and I’m greeted by some horrific blurry UI thing with a list of MAME games and settings! So it would seem that by default, start and select quits the game and takes me to some form of MAME UI (not retroarch). I thought of a way to get around this problem: I went into retroarch settings, configured the “select” button as hotkey and “start” as quit retroarch. Great, I thought. That’ll show it.
So now my bloody Select button won’t “insert coin”!!! I tried to figure a way around this (I don’t like to compromise, I don’t want to use a different button!). It’s like setting up retroarch’s hotkey as “select” takes away MAME’s ability to accept the “select” button to insert coin! Strangely though, if I go to MAME settings (Tab) and try to set “Player 1 coin” as the select button, it detects the button press fine and sets it to "Joy1 button 6 (or 7 maybe, I get those mixed up). However, returning to game and pressing the select button does nothing. 
Can anyone shed some light on this? I’m sure I’m just being stupid but I’m tired now of messing about in retroarch and mame menus! BTW, I don’t have this problem using the other retroarch cores- select and start quit the game and send straight back to frontend.
Please, please help!!!