Why disallow background color for custom views?

[nathansalaun-sofia]

This line https://github.com/Daltron/NotificationBanner/blob/master/NotificationBanner/Classes/BaseNotificationBanner.swift#L194 prevents setting a background color when there is a custom view.

Is there any reason why this is necessary? Or is it just an artificial limitation?

When I remove the guard, the background color still seems to work fine.

[reshmaraghu]

I see a fix was proposed, but not accepted.
#341