Add History / Update Order Status Button won't work

I had to remove OpenBay from my VQMOD completely and ended up manually having to edit / remove the extension. I made sure to only remove OpenBay instances which appeared in my order files, but for some reason, now I can click on the "add history" button when viewing an order, but it does nothing. I'm not sure if it's related to this OpenBay manual removal, but the button was working perfectly this morning (prior) to this.

Which file do I go to to check if my order history button is setup correctly? Any help is appreciated - I currently can't update my order status or add notes to orders.