Using xfce4-keyboard-settings, I have SuperL keybound to start rofi using rofi -show drun, but this prevents me from using SuperL in combination with any other key combinations, such as Super + L to lock the screen. rofi is hijacking the show immediately.
I've tried prepending a sleep to rofi, ie. sh -c "sleep 1 && rofi -show drun", which correctly sleeps and even lets me use Super + L to lock the screen, but then rofi loads over the top and starts to interact weirdly (read: undesirably) with the lock screen.
Is there a way that I can have both keyboard shortcuts work as desired without interfering with eachother?
BTW, the lock screen I'm using is i3lock-fancy.
I solved this following AndreLDM's advice.
I installed xcape, and added xcape -e 'Super_L=Control_L|Escape' to ~/.config/openbox/autostart and bound the keyboard shortcut Ctrl+Esc to run rofi. I was then able to keybind Super+L to i3lock-fancy and have both keyboard shortcuts work as I intended. Pressing Super by itself presents my rofi drun menu, and Super+L locks the screen.