code: func mod2mask(cks uint32) ModMask {
  	mm := ModNone
  	// Left or right control
  	if (cks & (0x0008 | 0x0004)) != 0 {
  		mm |= ModCtrl
  	}
  	// Left or right alt
  	if (cks & (0x0002 | 0x0001)) != 0 {
  		mm |= ModAlt
  	}
  	// Any shift
  	if (cks & 0x0010) != 0 {
  		mm |= ModShift
  	}
  	return mm
  }
docs: // Convert windows dwControlKeyState to modifier mask