If tabs and paging were re-using the creative inventory assets and layout:

• It would unify the rendering and layout.
• Avoid loading more resources.
• Allow a proper rendering with existing resources-packs without having to update it.

Default textures rendered creative inventory tabs;

Resources-pack rendered creative inventory tabs:

Great idea, I'm using right now faithful resource pack and that's how it looks like.

Fixed. There's now an option to use creative or JEI style tabs. The JEI style tabs also use a new resource so they won't conflict with existing resource packs that don't support them.