Start writer:

1. Tools / Macros / Organize Dialogs
1.5 select "Untitled 1", the brand new file
2. New Dialog
3. Edit dialog
4. Press 'Manage Language' toolbar (may need to enable Language toolbar in Views)
5. Add a language

No language is added.

This is because there is no localization for this dialog, and we get to:

basctl/source/dlged/managelang.cxx:

IMPL_LINK_NOARG(ManageLanguageDialog, AddHdl)
{
    ScopedVclPtrInstance< SetDefaultLanguageDialog > aDlg( this, m_xLocalizationMgr );
    if ( RET_OK == aDlg->Execute() )
    {
        if (!m_xLocalizationMgr->isLibraryLocalized())
        {
            SAL_WARN("basctl.basicide", "Adding langs to non-localized library tdf#93077");

This code-path =)

We need to have enough information at this point to do something intelligent like:

// XStringResourceSupplier
Reference< resource::XStringResourceResolver >
    SAL_CALL SfxDialogLibrary::getStringResource(  ) throw (RuntimeException, std::exception)
{
    if( !m_xStringResourcePersistence.is() )
        m_xStringResourcePersistence = m_pParent->implCreateStringResource( this );

    Reference< resource::XStringResourceResolver > xRet( m_xStringResourcePersistence, UNO_QUERY );
    return xRet;
}

Which creates the thing if it is not there =) cf. the related UNO API for that. But this will need more information passing into the dialog from the IDE code - in order to manage that; it'll ultimately be something like:

                Reference< XStringResourceWithLocation > xStringResourceWithLocation =
                    StringResourceWithLocation::create( xContext, aURL, bReadOnly,
                        xStringResourceResolver->getDefaultLocale(), aDialogName, aComment, xDummyHandler );


Thanks ! =)