Remove mixins that you no longer use to keep the skin of your application better organized and more convenient to navigate. When you delete a mixin, you must update the mixins that reference it manually.
You cannot delete inherited mixins. If you override an inherited mixin, you can only revert it to the original state.
In the navigation pane of Dev Studio, click Records.
Expand the User Interface category, and then click Skin.
Open the skin that you want to edit.
On the Mixins tab, click My Mixins, and then click the mixin that you want to remove.
In the settings pane in the middle of the screen, click.