How to get my [solid mode] object OUTLINES back? I don't know how this happened, but suddenly, my OGL object outlines (in object mode) are now gone. This makes it difficult to see object edges when they are placed adjacent to other objects. I need the object mode outlines back, but HOW?
There are a couple places you can enable outlines. The first is within the viewport, to highlight selected and active objects. You can find that option here: 


The other is in the object properties, here:


Enable wire to see the black edge outlines regardless of selection. Enable "Draw All Edges" to display all edges, whether coplanar or not. By default, coplanar edges are not drawn.