Users of languages that are written from right to left, such as Arabic, Persian and Hebrew, require special support in many applications, including those provided by the Mozilla project: the web browser and the mail & newsgroups client. Not only is backend support required for manipulation and display of content in different directions - such as is to be found, usually to satisfaction, in the Mozilla suite, the Firefox browser and the Thunderbird mail client - necessary, but the user interface for making use of such capabilities must also be made available.
For this reason the BiDi UI project @ MozDev exists: to offer extensions which provide user interface for direction control and use of direction-related unicode features, as well the smoothing over of some kinks in underlying BiDi support.
Currently, two extensions are available:
- BiDi Mail UI, for the Mozilla suite and the Thundebird Mail&News clients
- BiDi Browser UI, for the Mozilla suite and the Firefox browsers; this extension is partly obsolete (see link for details).
Both of these partially correspond to BiDi-related bugzilla bugs (see the two subsections for bug numbers), and can also be thought of as workarounds for them.