additional moduls panel won't disappear in DTPO 2.7.1?

Is this a bug or a feature at Mavericks? I’ve all modules despite Chrome and Safari extension and Jot 2. Then entered »Install«. Now the extensions in Firefox and obviously are installed but the panel won’t disappear. When I push the »Abbrechen« button - What is it’s name on english GUI? - nothing happens. The panel persists.

Has somebody an idea how to let disappear the modules panel?

Thanks in advance for your support! And kind regards, Friedrich