Why can't I close or edit my LO document? It's like it's frozen.

I’m trying to close a document I’ve worked on and it seems like it’s frozen. It won’t allow me to edit it or close it. No tabs are highlighted to even be an option to use. Any ideas? TIA

This seems to be a known issue in some previous 5.x versions.
I just installed 5.1.2 & since then no issues anymore. (windows 10)

for me this has been an ongoing issue for months after LO has been inactive for hours. usually with “lo not responding”. my work around = a windows restart & LO recover file gets me going again.