[TYPO3-rte] button "acronym" not shown any more for BE_users

[Stephan Bernhard]

hi list

since upgrading to version 4.3.3 the button "acronym" is not shown 
anymore for BE_users, although the following settings are unchanged:

- "acronym" is in the list of "allowTags" in Constants
- "showButtons = *" is set in user-TSConfig and page-TSConfig

interestingly the admin's can see and work with this button as before.

has there be a change for BE_users?
where would I change settings in order to allow the BE_users to see this 
button again?

thanks for any hint and help

stephan