I've used off centre projection to create a custom projection matrix for my camera.

When I run the game I can see the scene correctly in the game view but in the editor view the camera frustum is not correct. It still shows the original frustum shape not the new one.

It also appears that Unity is using the original frustum for frustum culling and not the new one as I can see object being culled which are visible to the new frustum but would not be visible in the old one.

Am I wrong in thinking that a custom projection matrix would alter the view frustum? Or am I missing something else?