Background reflected in glossy glass, but I didn't set it I've made a roughness 0 glass pane, when I'm in lookdev mode it's reflecting a background that I didn't put there. I know I could just ignore it, but I'd rather be able to see what it'll mostly look like when I'm in the later stages. I also just want to know how on Earth I managed to set this background without realising it

Reflection completely ignores any objects I put in front of it. If I placed this glass inside my house, it would still just reflect trees (This is the point where I felt I couldn't ignore it - reflections are going to play a big part in my project and I don't want to be in render mode all the time)

The nodes are the default glass BSDF, except I set roughness to 0

The glass is set to 20mm thick, if that makes a difference

The background moves with my perspective and moves when I relocate the glass

I have a few HDRI's on my PC, but none look remotely like this 

Also, I'm using cycles as I find Evee buggy as hell
Lookdev mode uses Eevee under the hood overrides certain lighting parameters for a faster, simpler preview. The idea is for it to provide a reasonably general lighting setup out of the box without needing configuration, enabling users to quickly develop how their materials look. 

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