setxkbmap -query
    rules:      evdev
    model:      pc105
    layout:     us
    options:    shift:both_capslock_cancel,caps:escape,srvrkeys:none

Pressing Left Shift:
    KeyPress event, serial 79, synthetic NO, window 0x6600001,
        root 0xf1, subw 0x0, time 230695223, (597,319), root:(920,585),
        state 0x10, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
        XLookupString gives 0 bytes:
        XmbLookupString gives 0 bytes:
        XFilterEvent returns: False

    KeyRelease event, serial 79, synthetic NO, window 0x6600001,
        root 0xf1, subw 0x0, time 230695270, (597,319), root:(920,585),
        state 0x11, keycode 50 (keysym 0xffe5, Caps_Lock), same_screen YES,
        XLookupString gives 0 bytes:
        XFilterEvent returns: False


Pressing Left + Right Shift:
    KeyPress event, serial 79, synthetic NO, window 0x6600001,
        root 0xf1, subw 0x0, time 230844852, (312,312), root:(635,578),
        state 0x10, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
        XLookupString gives 0 bytes:
        XmbLookupString gives 0 bytes:
        XFilterEvent returns: False

    KeyPress event, serial 79, synthetic NO, window 0x6600001,
        root 0xf1, subw 0x0, time 230846116, (312,312), root:(635,578),
        state 0x11, keycode 62 (keysym 0xffe5, Caps_Lock), same_screen YES,
        XKeysymToKeycode returns keycode: 50
        XLookupString gives 0 bytes:
        XmbLookupString gives 0 bytes:
        XFilterEvent returns: False

    PropertyNotify event, serial 79, synthetic NO, window 0x6600001,
        atom 0x199 (XKLAVIER_STATE), time 230846120, state PropertyNewValue

    KeyRelease event, serial 79, synthetic NO, window 0x6600001,
        root 0xf1, subw 0x0, time 230846171, (312,312), root:(635,578),
        state 0x13, keycode 62 (keysym 0xffe2, Shift_R), same_screen YES,
        XLookupString gives 0 bytes:
        XFilterEvent returns: False

    KeyRelease event, serial 79, synthetic NO, window 0x6600001,
        root 0xf1, subw 0x0, time 230849488, (312,312), root:(635,578),
        state 0x13, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
        XLookupString gives 0 bytes:
        XFilterEvent returns: False