Blender version 2.77a (According to splash screen)
In this image, you can see the outline of a selected/active mesh on the right-hand side. The 2D background image is an "Empty" entity assigned to it an image. On the left-hand side you should be able to make out the black outlines of non-selected/inactive meshes. Everything normal so far.
The left-hand meshes were created before the Empty was created. (I had the image opened in GIMP and modelling the mesh within blender on its own.) This is a brand new file. No fancy options or anything. Literally started blender, deleted startup stuff, changed the world grid properties, enabled Snapping (to increment), and then created a "Grid" for each room and using Extrude and Subdivide to shape it.
The final bit of context/info: the image has a Z of 0. The meshes start as "Grid" at 0, but I extrude walls 200 above, and water pits 200 below 0. So they're 400 tall with the middle/floor being at 0.
Now here is the problem:
When I deselect the right-hand mesh, it disappears from view. It is still there, and if I hit Z to make meshes solid again, it will reappear.
If I change the angle with Numpad 1, the mesh re-appears when not selected, but the lines that are supposed to overlap the image disappear "behind" it regardless of what angle I'm looking at. On the left of the third image you should be able to see black lines going over the bright blue. The black lines do not go over the bright blue on the right-hand mesh.
So the point I'm trying to make is: Why do meshes created after an "Empty (Image)" disappear behind it? What can be done to fix this unwanted behavior?