I have been using this software for years and have never had a layout do this before. I think I accidentally clicked something and now all my active layout items are greyed out as if I paused them, like pausing the loading of a dataframe. Legend, dataframe, north arrow, and scale bar are all greyed out with a grey gradient. Layout text items display normally.
Has anyone had this happen before and does anyone know how to display these items normally again?
You do not mention whether you are aware of Draft Mode on the Frame tab of the Data Frame Properties.
However, this only greys out the Data Frame for me:
If you have not already done so, I would do a Save As on your map, or just Save if losing it would be survivable, and then close ArcMap, before restarting ArcMap to see if it starts to behave as you expect.