Since you didn't share any code, I can only guess what's wrong.
I suspect that you are setting both trackSkin
and secondaryTrackSkin
. In this case, they are displayed at the same time. The trackSkin
appears on the left side of the thumbSkin
, and the secondaryTrackSkin
appears on the right side of the thumbSkin
. They meet in the middle of the thumbSkin
.
On the other hand, the default theme sets only trackSkin
, but not secondaryTrackSkin
. When there is only a trackSkin
(and secondaryTrackSkin
is null
), the trackSkin
spans the entire width of the ToggleSwitch
.