$ xev | grep -i button
ButtonPress event, serial 37, synthetic NO, window 0x1e00001,
state 0x10, button 1, same_screen YES
ButtonRelease event, serial 37, synthetic NO, window 0x1e00001,
state 0x110, button 1, same_screen YES
ButtonPress event, serial 37, synthetic NO, window 0x1e00001,
state 0x10, button 1, same_screen YES
ButtonRelease event, serial 37, synthetic NO, window 0x1e00001,
state 0x110, button 1, same_screen YES