Created attachment 150103 [details]
Screen shot showing disabled menu entries

See the attached screen shot.

Opening the right click context menu for files showed most options disabled.
I did not attempt to click on a menu item marked as disabled or otherwise.
I had multiple tabs open.  The same effect was seen in all tabs.  There were no other Nautilus windows open.
I closed the Nautilus window.
There remained a nautilus process running.
Running nautilus to open a new window, the bug was not in effect: the context menu showed all entries active as usual.
I was owner of and had permissions to operate on the file. No unusual symptoms were seen in other software.

There are many errors and warnings, as usual these days in released stable software, in .xsession-errors.  See the attached text file for the ones from nautilus.

I did not experience this bug before and have not been able to reproduce it since.

I do not recall whether I looked at the file operations under the "File" menu option.