I want to use Tab to switch to the previously-used input source, and ⇧ ShiftTab as the usual tab function.
As a Chinese language user, the key combination I use the most is ⌘ CommandSpace, which selects the previous input source. Since I only have two keyboards enabled, selecting the previous input source is the same thing as toggling between them. For every non-English user, this switch is frequent.
To make it easier, I want to use Tab to switch input sources. Following this, a ⇧Tab sounds like a good idea to perform the normal function of Tab.
However, System Preferences (as I tried it) only allows the user to set the switch as a combination starting with ⇧ Shift or ⌃ Control. Is my request unreasonable? Or can it be done?