Cannot close apps

invalid@example.com (Pastorhss), Pastorhss
Mon, 29 Oct 2018 15:09:43 +0000
Samsung Chromebooks

I have a Samsung Chromebook Plus. For some reason, for the past few days, once I open an app I cannot close it - with the X at top right or with Task Manager. (end process greyed out)

I also noticed that when in the Chrome Browser, I no longer see an extra tab so that I can open another window.

Can anyone help? Thanks.