@Daeraxa alright thanks for the advice
@theCollectiv recently I found out about the immediate cause why the default shortcut Ctrl+Shift+S/L (to "focus" on side bar and notes list) didn't work last time. If I hide the sidebar and the notes list by pressing F10 and F11, then un-hide it again with the same keys, the Ctrl+Shift+S/L is deactivated.
I thought it was because I used Vim and Vim has some key mapped to the aforementioned keys that I didn't know.
The shortcut keys for focusing to notes list and sidebar works again if I turned off the app and started it up again.
Do you think this is a bug? or an intended purpose?