Duplicate Viewport Function Not Working

Today, I went to duplicate a viewport, like I had been doing all morning, and the function in the “Edit” menu is greyed out. What did I do? Has anyone experienced this problem?

Had you selected a viewport first? Or did you have more than just the viewport selected?

Yes. I selected the viewport as I have always done. Only one viewport.

Maybe you could share the LO file (privately if you wish) and tell me which viewport you’re trying to duplicate.

Thanks for your quick response and willingness to help. I just nudged the viewport slightly, and the duplicate function came back one. Go figure.