Earlier this month, drawing app developer Astro HQ released a video of a really clever new idea for its apps: it turned the iPad’s front camera into a button, letting you tap on the lens to activate things on screen. It was a smart way to free up screen space, but as it turns out, Apple doesn’t agree. Astro said today that its app was rejected from the App Store for violating Apple’s guidelines.

In particular, Apple pointed to a section saying that apps couldn’t “alter or disable the functions of standard switches, such as the Volume Up/Down and Ring/Silent switches, or other native user interface elements or behaviors.” While Astro’s app, Astropad Studio, wasn’t strictly altering a switch, it did make the camera stop acting like a camera, which seems to at least break the spirit of the rule.

Apple is extremely strict about what it does and does not allow into its App Store, so this rejection isn’t a huge surprise. The company uses its position as a gatekeeper to make sure that apps don’t alter the experience of using its devices, maintaining consistency in a way that’ll be clear to users. It seems hard to argue that a small tweak like this in an app meant for professional illustrators really would have had a deleterious effect on the platform, but Apple has rejected apps for less.