How can I switch b/w multiple windows in 'Preview' on Mavericks by keyboard shortcut?

On previous versions of OS-X own Apple application 'Preview' honoured system-wide shortcut CMD-< for switching to next open windows.

This is still shown under 'Preferences' -> 'Keyboard' on Mavericks (screenshot in German - please bear with me 😉 ):

However, 'Preview' on Mavericks does now overrule this keystroke (at least in German version - only?) for command 'Togggle icon bar':

Therefore I would be grateful for hints about:

- how to toggle b/w windows in 'Preview' on Mavericks by shortcut a/o

- how to get previous (system-wide!) functionality of CMD-< back for 'Preview' on Mavericks?

Any help highly appreciated - Thank you very much in advance.

P.S.: Do you think, this should be considered a violation of Apple's own design guideline - overruling a system-wide defined shortcut in Apple's own application?