Lost hero icon on the slider - TF3D sprint TP

[speck]

I was trying out new icons and sliders with manila customizer - and something went wrong - I forgot to undo between changes. Now I want the original icons and slider back. I've got the original icons (I think) and the original slider (again, I think), but the 'hero' icon (the colored outline of the icon) doesn't show on the slider - but it does show in the main area when switching between tabs. What controls seeing the icon on top of the slider?

I hope this makes sense.