I'm currently discovering the reworked UI of Blender 2.8. I have some kind of cube, cut in half, mirrored to a full cube again using the mirror modifier. In edit mode, I've noticed some changes that I personally dislike.
It could be a bug, a feature, or just a default setting: I'm only seeing the half mesh that I'm able to edit, the other side is simply not shown. In previous blender versions, you could always see the mirrored part, here it is completely gone.
Also, if I'm using subdivision surface, I can only see the real model in edit mode, without the filter "applied".
Here are two screenshots showing a similar model in edit mode:
Do you know if this is just a simple setting?