kTertiaryButton top-level constant Null safety
The bit of PointerEvent.buttons that corresponds to a cross-device behavior of "tertiary operation".
It is equivalent to:
- kMiddleMouseButton: The tertiary mouseButton.
- kSecondaryStylusButton: The secondary button on a stylus. This is considered a tertiary button as the primary button of a stylus already corresponds to a "secondary operation" (where stylus contact is the primary operation).
const int kTertiaryButton = 0x04;