It seems that in 2.80, if you have an object without thickness that is aligned with the view axis, it completely disappear in wireframe view/shading(?) and object mode.
I made an example with a plane and an extruded square shape. Both are clearly visible in 2.79 top and side view, but invisible (or nearly invisible) in 2.80.
I’m in object mode and wireframe mode, all objects deselected, no special setting (only the default that comes when you 1st start blender). The solid mode doesn’t help much more: for both 2.7x and 2.80 the plane is invisible on the side view and the extruded shape is invisible on the top view (hence why I used the wireframe mode on 2.7x, but now it’s unusable).
So… am I the only one affected by this? Or am I missing an obvious setting? It makes 2.80 a pain to use.