LyX ⇒ Language changed to Greek

[cute_audrey]

I tried to get the Euro-sign like explained on this site: http://jhau.maliwi.de/linux/textproc.html
It says: "To use the EURO symbol (€) in LyX, insert a TeX box, and write \euro{} inside. Mark the entire box and change the language of the marked box to Greek - this is necessary since \euro (without any packages) works in Greek but not otherwise.

(Thanks to Helge Hafting) "

Unfortunately I somehow changed language of the whole document to Greek. I already tried to mark the document and change the language back to German with documents --> options --> language but it doesn't work.

The LaTeX-source windows shows me \lang greek in front of every paragraph, but I can't export the document into LaTeX-code, fix the problem and transform it back.

How do I change back to German language? Any hidden secrets? That problem is driving crazy!