Comment 2 for bug 1763953

Do you have interest to look into this yourself?

I think you need to edit this file:
https://github.com/mixxxdj/mixxx/blob/12da5a54eedba3376ea2186dcb4cf01d4e1a6b8a/res/skins/Deere/sampler_controls_row.xml

and add something like

<Template src="skin:mixer_column_gain_levels.xml"/>

or the content of mixer_column_gain_levels.xml