Using Ctrl+PageDn to switch tabs in GTK+ moves to the next tab and vice versa for Ctrl+PageUp, but Ctrl+Shift+PageUp works backwards in SVN terminal. My locale is set to a LtR one (en_US), for what it's worth.
Uhm, Ctrl+Shift+PageUp isn't used by Terminal (atleast for the default config). The default shortcut for "Previous Tab" is Ctrl+PageUp, and Ctrl+PageDown for "Next Tab". Did you assign new shortcut keys to these actions?
Hmm, could be that I'm just a mite bit confused. ps shows the running process as 'xfce4-terminal', but my package manager (which manages Xfce SVN also) says that xfce4-terminal-svn (the package) replaces Terminal. Is this a confusion of the package?
Dunno about your packages. Check Edit->Preferences->Shortcuts, esp. the shortcuts assigned to "Previous Tab" and "Next Tab".
OK, I'm very sorry for the confusion, but it's xfce4-terminal that I'm running, not Terminal. So AFAIK, there aren't any configurable shortcuts for it.
So, this is INVALID then.