It may happen, that on specific systems with certain font screen
flickering might occur. By setting new resource
'URxvt.tabbedalt.stop-flickering' to true, it'll prevent this.
In my derivation I arbitrary choose ctrl+shift+n as a shortcut for
creating new shell tab. There was a bug, when user created some other
class (for example for midnight commander and root) and with such
configuration it will unable to create default shell tabs.
This change introduces standard shortcut from original tabbed extension
(shift+down) as a default one for creating shell tabs. All the shell
classes can be configured and used as before.
Shift+down shortcut can be disabled, and now, "new style" - ctrl+shift+n
shortcut would be used for that purpose, unless user provide its own
class definition for that shortcut, than user responsibility is to make
appropriate shortcut for default shell.
gryf