This is implemented in [r2083] now. Await the next release...
* updated further German translations
- add help for new RegEx button
* updated several German translations
* updated some translation bugs (German translation)
* add-on to FR#306: Allow actively applying RegEx in UI
OK, I guess I know whats happening for you: It is working as expected but likely you are entering the RegEx and not closing the log dialog. In that case, the actual expression is not persisted in the config and therefore does not become active. I will add an "apply" button such that the user can actively save the RegEx such that it gets applied in such cases. I see that this is ambiguous behaviour otherwise...
According to the RegEx Testbed in WCM it is supposed to work with the RegEx given above, at least...