When I click the diskette, then close tab, then reopen it with Ctrl+Shift+T, message form is empty.See screenshot below.......this may help save you from the dreaded "ooops...I closed it"
Could be that you are using a browser extension or functionality that automatically blocks certain website functions, because this works for me as well.When I click the diskette, then close tab, then reopen it with Ctrl+Shift+T, message form is empty.