Here it is:
Suddenly the lines aren't appearing on shapes in the stencils. For ex., on the Cross-functional stencil, the separators have no lines showing at all.
And 1/2 pt outlines on shapes in the doc don't appear if I zoom out to less than 100%. 3/4 pt lines appear at 75% zoom but not less than that. 1 pt lines at 67% but not less than that.
This wan't happening 2 days ago, the last time I used Visio.
I was always able to see the outline around the shapes no matter how far out I zoomed. Also note that you can't tell that one of these shapes is a predefined process without being able to see the lines.