Hello again!
I put a music file in the /SHARE/music/ folder to play on the menus but instead the music changes when ever I click left or right to another music from the default ones. Another click and the music changes back to mu custom music but this goes on and on. I didn't do anything, I just put one music file in the folder.

Ah, I found the answer.

I had to install a standalone Retroarch to apply the hotkey combo and then check the retroarch.cfg file for the value.

The answer is to disable the menu hotkey like this:
"input_menu_toggle_btn = "nul""

And use a line specific for the combo which is this one:
"input_menu_toggle_gamepad_combo = "3""
where "3" is the order of the combo in the combo list. "0" is none so it's actually the fourth selection.

Cheers!

Hello! You guys put Batocera/Retrobat to shame (figure of speech, not that they are bad). Thank you for (almost) putting everything I wanted on a frontend. Thank you kindly.

I said almost because I still cannot find a way to set the hotkey menu shortcut to the L1+R1+Select+Start option Retroarch natively provides. I read some posts that combos are not possible, but in this case the option exits in Retroarch natively so I'm asking how.

I managed to make my own custom hotkey shortcuts and now I only have Select+Start(twice) to quit games and Select+L1 to show Retroarch menu (all others are disabled). I tried setting up the buttons for the combo I mentioned above and they are 4, 5 and 9 on my RetroBit Genesis 8-button controller working on Nintendo Switch mode (L1, R1 and Start respectively). But only button 4 was taken.

Here's the line on .retroarch.cfg:
"input_menu_toggle_btn = "459"" and I tried adding + among them but no use.

The Hotkey is 8 so I didn't put it.

What is the correct formula for it?

When in the configuration select "ON" for "Save Configuration on Quit"
(why this is not set to on from the start is beyond me)

I'm on a fresh installation (almost) and it is set on "on". Maybe you did something that changed it by mistake.