enum Button {
SoSpaceballButtonEvent::ANY Any spaceball button
SoSpaceballButtonEvent::BUTTON1 Spaceball button 1
SoSpaceballButtonEvent::BUTTON2 Spaceball button 2
SoSpaceballButtonEvent::BUTTON3 Spaceball button 3
SoSpaceballButtonEvent::BUTTON4 Spaceball button 4
SoSpaceballButtonEvent::BUTTON5 Spaceball button 5
SoSpaceballButtonEvent::BUTTON6 Spaceball button 6
SoSpaceballButtonEvent::BUTTON7 Spaceball button 7
SoSpaceballButtonEvent::BUTTON8 Spaceball button 8
SoSpaceballButtonEvent::PICK Spaceball pick button
}