Weeks later...

Since this "Game Focus Mode" feature was definitely not practical (the user has to press a key to use the keyboard, and then press a key again to access the shortcut to return to EmulationStation, it's a pain...), I found it much more useful to remove all the shortcuts that RetroArch assigned to the keyboard keys.

(Honestly, I wonder WHO thought it would be a good idea to use all the keys on a keyboard to provide shortcuts that nobody ever uses... when you're emulating a machine that needs a keyboard to work)

(especially when one of those shortcuts is used to display... a virtual keyboard).

So, I edited the /opt/retropie/configs/amstradcpc/retroarch.cfg file, and changed (or added) all the following 'input' lines to 'null':

input_exit_emulator = "nul" input_player1_l = "nul" input_player1_r = "nul" input_hold_slowmotion = "nul" input_rewind = "nul" input_cheat_index_minus = "nul" input_cheat_index_plus = "nul" input_cheat_toggle = "nul" input_netplay_game_watch = "nul" input_movie_record_toggle = "nul" input_pause_toggle = "nul" input_player1_y = "nul" input_player1_x = "nul" input_toggle_fullscreen = "nul" input_reset = "nul" input_frame_advance = "nul" input_hold_fast_forward = "nul" input_player1_start = "nul" input_player1_b = "nul" input_player1_a = "nul" input_shader_prev = "nul" input_shader_next = "nul" input_player1_select = "nul" input_toggle_fast_forward = "nul" input_player1_up = "nul" input_player1_left = "nul" input_player1_right = "nul" input_player1_down = "nul" input_volume_down = "nul" input_volume_up = "nul"

I'm now doing the same for all the other emulators that have the exact same problem (all the libretto cores that emulate a computer: lr-atari800, lr-bluemsx, lr-fuse, lr-theodore, lr-vice...)

CapriceRPI missing from optional / experimental packages?