On Windows the platform provides the right click emulation for pen input by doing long press. This allows widgets that were not designed to work with pen input to be usable with pen instead of mouse without any major limitations. Currently Qt translates unhandled pen events (QTabletEvent) to left mouse button events, while right mouse button events are synthesized by the platform. However, this feature exits only on Windows and on Linux Qt should synthesise right click events form pen events itself when they are needed.

This problem is similar to QTBUG-73949