#407 Range slider stutter in TDDisplayFX

[Jamie Mac]

The range slider in the TDDisplay stutters if the track is dragged (rather than the thumbs). It is difficult to move the range slider. This is a problem with the ControlsFX library and introduced to PG in the process of getting rid of the Skin classes copied directly from earlier versions of the library. A bug report has been filed with the library. Hopefully version 8.15 of ControlsFX will solve the issue (PG currently uses version 8.12/14).