Operating system: Windows 10 Home x64
Graphics card: GTX 1080 Ti
blender 2.8, 2018-12-04 - 04:09
Branch: blender 2.8
The selection of vertices on wireframe or xray mode is broken. After moving a vertice on Wireframe mode you can only pick up the same vert again by clicking on its previous position, not on it's current position.
Draging a selection box or using the selection brush around the vert doesn't do anything either.
A way to fix it is by changing from edit mode to object mode and back to edit again, this way you can select the vert by clicking on it and not on its previous location.
This bug is very frustrating, specially when modeling in ortho trying to match a background sketch/picture.
The bug is very easy to replicate:
1. Open any file with any geometry in it;
2. Turn on Wireframe mode;
3. Move any vert away from the geometry;
4. Try picking the same vert again;
5. Try clicking on the previous location of the vert and see the same vert that is now far away being selected.
I've tested this with the latest 5 or 6 builds of Blender 2.8 and the bug still exists.