Broken language switch when moving in browser history

If the language in the url changes via a history.back, the language selector and the language of the page do not change.

This was caused by 3ecacadc.

assigned to @pbeke

mentioned in commit 421d92f3

mentioned in commit dbp/esign/signature@45d6ad1e

Fixed now.

closed

mentioned in commit 4a73c52d

4be86c89 is even a better fix.

mentioned in commit dbp/check-in/checkin@c6ac9871