I'm struggling to get the layout to display normally. In the past, the layout has displayed the paper with an adjustable data frame which I can resize freely. Currently, when I switch to layout, the base map continues to occupy the whole screen, and there's no adjustable border and no sign of the actual paper (see image). Does anyone know what's going on here?
Edit: I'm using ArcMap 10.5.1 I've explained more in the comments. I can still export the layout map, and the exported image appears correctly, but the actual layout view is unchanged from the image.