Multiple styles in a single axis value doesn't work

[heftig]

Using Styles = style 1 || style 1,style 2 in the UI produces an error:

RuntimeError: Invalid axis 2 'Styles':
  errored: value 'style 1,style 2'
  errored: Invalid parameter 'styles' as 'style 1,style 2':
  not matched to any entry in list ['style 1', 'style 2']

It seems the value validation expects a single style for each value, even though apply_styles will split the value at , later.

(PS: apply_styles should probably also strip each style after splitting to ignore surrounding whitespace.)