Original report by jonathan millman (Bitbucket: millmanorama, GitHub: millmanorama).
When the user clicks on the track to the left of the range, the low thumb is re positioned. But when the user clicks to the right of the range, the low thumb is also re-positioned but clamped to the high thumb. Instead the high thumb should be re positioned.
该提问来源于开源项目：controlsfx/controlsfx
