Collision shows but isn't there

I have imported the following mesh and clicked on the collision tab, which results in the following attached image. As you can see, there are green lines around the mesh which disappear when toggling off the collision tab above. However, the number of collision primitives is listed as 0, and sure enough, there is no collision when brought into the world.

Do the green lines denote something other than collision or is this a bug?

Awesome, thank you so much!

These cyan looking lines show the tris of your Static Mesh. It’s possible to use these lines as collision if you go under settings, and type “collision complexity” in the search bar and change the settings to “use complex collision as simple”.

However, for collision you always want to make something less complex. You can add simple primitives like box, sphere and capsule and build something with them to match your house. You can find more information about how to set these up on this page. If you have more questions about collision, feel free to ask, otherwise, smash the resolve button on this question! <3