Bug - Weapon Focus for Orc Horn Bow
 

I don't know if this is repeated with other racial weapons, but...

I have a Half-Orc character with Martial Weapons Proficiency, and Hero Lab correctly recognizes that the Orc Horn Bow is considered a martial weapon for him (rather than exotic), and he's proficient with it. So far, so good.

However, when I then take the Weapon Focus feat, and select Orc Horn Bow, Hero Lab tells me that I can't take the feat for the weapon because I'm not proficient with it.

Does it work if you select "Composite Bow" for Weapon Focus.
In any case I'd submit a bug report.