private @Nullable ServiceViewContentHolder getContentHolder(@NotNull Class<?> contributorClass) {
    for (ServiceViewContentHolder holder : myContentHolders) {
      for (ServiceViewContributor<?> rootContributor : holder.rootContributors) {
        if (contributorClass.isInstance(rootContributor)) {
          return holder;
        }
      }
    }
    return null;
  }
private @Nullable ServiceViewContentHolder getContentHolder(@NotNull Class<?> contributorClass)