The default icon settings are currently ignored because (I assume) you generally want different icon settings for each individual blueprint to number them. I do think it could be a useful "default" setting anyway though I can think of two different ways to implement it.
Append the icons of the default settings to the individual blueprints. This would let numbering still work, and you could add more icons to individual blueprints if needed while still allowing for a broad icon to mark the book at large (say a steam engine for a power plant).
Have the default icon settings provide the icons for the generated book. Not really a default, but it would allow configuring the icons of the book which would make it easy to differentiate different blueprint books on the hotbar.
It is a minor issue in the grand scheme of things but I figure it is better to create the issue and have it closed than not creating an issue at all.
The default icon settings are currently ignored because (I assume) you generally want different icon settings for each individual blueprint to number them. I do think it could be a useful "default" setting anyway though I can think of two different ways to implement it.
It is a minor issue in the grand scheme of things but I figure it is better to create the issue and have it closed than not creating an issue at all.