I changed my IntelliJ settings to save .properties files in ISO-8859-1, instead of "System Default", and the original file was modified to work properly. But, since any subsequent editing by anyone with the incorrect settings in their editor could potentially break it again, I think that using the newly contributed version that uses explicit escaping is probably best, in a defensive programming sort of way.

Subversion 18416
icefaces\samples\component-showcase\common-src\org\icefaces\application\showcase\view\resources\messages_de.properties

According to the specification ( http://java.sun.com/j2se/1.4.2/docs/api/java/util/Properties.html ), a properties file should always be loaded with ISO 8859-1 character encoding, however there might be OS dependent changes to that, so I tried to provide an escaped file instead.
Can you please take a look at it and tell me if it is working now?

For message.properties files, used in JSF applications, there are special file format limitations that have to be taken into account. One of them is that you can't really use non-ASCII characters, but should instead use Unicode escape sequences. For example, instead of using "á" (a/), you would have to give "\u00E1". The German translation needs to be modified, to work around this limitation.

Added new German language bundle to component showcase with two corrections sent by contributor. Also updated duplicated page content that where duplicated for each language but had now local specific text. These files where flattened and local specific text was moved into message bundles.

User contributed corrections to the attached resource file:

Manual Klein reports that he found two errors:
tabbedHeadings.source.iframeMessage = Iframe wird nicht unterstürzt. Nutzen Sie diesen Link um den Quellcode zu sehen.
unterstürzt is wrong, correct is unterstützt

page.panelTabSet.example.icePdf.description = Die führende Lösung zum Java PDF Dokumenteb Rendering...
Dokumenteb is wrong, correct is Dokumenten

German resource file attached.

I'm working on the German translation and will provide the messages_de.properties file begin of next week.