For charts with multiple layers, you can now apply Pipeline steps to a single layer prior to the Merge step.
Switch to the layer you want to apply a Pipeline step to.
Click the +Add Step button located above your Merge step.
Select your Pipeline step from the +Add Step dropdown. The title bar of the Pipeline step will display the Layer name to which the step is applied.
Note that any Pipeline steps applied to individual layers are only visible when that layer is selected.