Running on Mac, 10.13.2, Thunderbird pulls emails from Gmail account. Problem began today where my buttons, just above the message pane, for delete, junk, archive, etc disappeared. Can still delete emails from the inbox by hitting the delete button on the keyboard but something has gone awry. Now, I cannot access the subfolders under the main folder. They are all listed and some even show that they have new unread emails in them (based upon the bold text) but when I try to click on them they do not open. Then when I try to click back on the Inbox and check new emails there it does not respond. If I restart application then I can access the inbox emails again. Once I restart application then whatever subfolder I click on opens and I can access all emails in that folder but if I try to click on any other folder it does not respond and then I cannot go back and access emails in the originally opened folder. Thanks for any help.