You can test whether it is a translation issue by changing the user interface language in 'Datei > Inkscape-Einstellungen > Benutzeroberfläche > Sprache' to 'Englisch' and restart Inkscape.
OTOH 'Neues Fenster' or 'New Window' did not exist in 0.46 and does not exist in 0.47 on OS X 10.5.8.
In Inkscape 0.47 there is
a) 'Datei > Neu' or 'File > New' - the top entry of the file menu - which lists all available templates, and only 'default' if no templates are found
b) 'Ansicht > Fenster Duplizieren' or 'View > Duplicate Window' to open a separate window with the same document.
You can test whether it is a translation issue by changing the user interface language in 'Datei > Inkscape- Einstellungen > Benutzeroberfläche > Sprache' to 'Englisch' and restart Inkscape.
OTOH 'Neues Fenster' or 'New Window' did not exist in 0.46 and does not exist in 0.47 on OS X 10.5.8.
In Inkscape 0.47 there is
a) 'Datei > Neu' or 'File > New' - the top entry of the file menu - which lists all available templates, and only 'default' if no templates are found
b) 'Ansicht > Fenster Duplizieren' or 'View > Duplicate Window' to open a separate window with the same document.