On 4 Jun 2012, at 07:46, Aller Spanninga wrote:

>  then the language instantly flips back to "English (U.S.)

Possibly you are checking a word at a time in Dutch and then your checker is reverting to English as default.

There is a set of flags at the bottom of your page.

Select ALL your text and then opt for the language you wish to check in and click on the corresponding flag.

T