* Start a new SeaMonkey browser session * Open a few tabs at various web sites * Kill the browser with an unexpected signal * Restart the browser - the "Restore Session" tab comes up * Open another tab * Return to the sessionrestore tab and press "Restore Previous Session" Actual results: - Another SeaMonkey window appears, but this window remains blank. - The "Restore Previous Session" button is greyed out and cannot be pressed again, but the sessionrestore tab remains open. - The following messages are logged in the Error Console: Error: uncaught exception: 2147942487 Source File: chrome://communicator/content/aboutSessionRestore.js Line: 116 Error: NS_ERROR_ILLEGAL_VALUE: Illegal value'Illegal value' when calling method: [nsISessionStore::setWindowState] Source File: chrome://communicator/content/aboutSessionRestore.js Line: 116 Error: TypeError: browser[name] is undefined Source File: resource://devtools/client/framework/gDevTools.jsm Line: 160 Error: TypeError: menu is null Source File: resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/browser-menus.js Line: 341 Expected results: - Session should actually be restored in some way. Workaround: - It turns out that if you close the new window and the extra tab, then reload the sessionrestore window, the "Restore Previous Session" button works again. Testing environment: Linux Fedora 26 x86_64, fvwm 1.24r window manager, seamonkey-2.46-3.fc26.x86_64