User Agent: Mozilla/5.0 (Windows NT 6.1; rv:52.0) Gecko/20100101 Firefox/52.0 SeaMonkey/2.49.2 Build ID: 20180205075051 Steps to reproduce: * seamonkey terminates unexpectedly (kill -9) * seamonkey is restarted, tab prompting to restore old session appears * open a new tab (variant: if seamonkey is the default browser click on a hyperlink in some other application when seamonkey is not running and seamonkey will start with two tabs - about:sessionrestore and this link) * go to about:sessionrestore tab and click 'restore previous session' button Actual results: a new blank window opens, session is not restored, 'restore previous session' button gets disabled. There is a workaround: * close all tabs except about:sessionrestore * click on any tab/window in the session restore list to de-select it - this re-enables 'restore previous session' button, and then select it back. * click the 'restore previous session' button Expected results: session restores. New tab probably should be kept too.