message: Better Catalog->Properties for non-PO files
  As the only configurable thing for XLIFF files right now is the
  language, don't show the full properties dialog. Use the language
  picker instead.
diff: @@ -1435,14 +1435,20 @@ void PoeditFrame::OnProperties(wxCommandEvent&)
  }
  void PoeditFrame::EditCatalogProperties()
  +{
  + switch (m_catalog->GetFileType())
  + {
  + case Catalog::Type::PO:
  + case Catalog::Type::POT:
  {
  wxWindowPtr<PropertiesDialog> dlg(new PropertiesDialog(this, m_catalog, m_fileExistsOnDisk));
  const Language prevLang = m_catalog->GetLanguage();
  dlg->TransferTo(m_catalog);
  dlg->ShowWindowModalThenDo([=](int retcode){
  - if (retcode == wxID_OK)
  - {
  + if (retcode != wxID_OK)
  + return;
  +
  dlg->TransferFrom(m_catalog);
  m_modified = true;
  RecreatePluralTextCtrls();
  @@ -1454,8 +1460,35 @@ void PoeditFrame::EditCatalogProperties()
  // trigger resorting and language header update:
  NotifyCatalogChanged(m_catalog);
  }
  + });
  +
  + break;
  + }
  +
  + // Only language can be changed for other file types:
  + case Catalog::Type::XLIFF:
  + {
  + wxWindowPtr<LanguageDialog> dlg(new LanguageDialog(this));
  + dlg->SetLang(m_catalog->GetLanguage());
  + dlg->ShowWindowModalThenDo([=](int retcode){
  + if (retcode != wxID_OK)
  + return;
  +
  + if (dlg->GetLang() != m_catalog->GetLanguage())
  + {
  + m_catalog->SetLanguage(dlg->GetLang());
  + m_modified = true;
  + RecreatePluralTextCtrls();
  +
  + UpdateTextLanguage();
  + // trigger resorting and language header update:
  + NotifyCatalogChanged(m_catalog);
  }
  });
  +
  + break;
  + }
  + }
  }
  void PoeditFrame::EditCatalogPropertiesAndUpdateFromSources()
  