code: public function handle(BuildDataDefinitionEvent $event)
      {
          if (($event->getContainer()->getName() !== 'tl_metamodel_rendersetting')) {
              return;
          }
  
          $palettes = $event->getContainer()->getPalettesDefinition();
  
          foreach ($palettes->getPalettes() as $palette) {
              if ($palette->getName() !== 'default') {
                  $paletteCondition = $palette->getCondition();
                  if (!($paletteCondition instanceof ConditionChainInterface)
                      || ($paletteCondition->getConjunction() !== PaletteConditionChain::OR_CONJUNCTION)
                  ) {
                      $paletteCondition = new PaletteConditionChain(
                          $paletteCondition ? array($paletteCondition) : array(),
                          PaletteConditionChain::OR_CONJUNCTION
                      );
                      $palette->setCondition($paletteCondition);
                  }
                  $paletteCondition->addCondition(new PaletteCondition($palette->getName(), 1, $this->connection));
              }
  
              $this->buildMetaPaletteConditions(
                  $palette,
                  (array) $GLOBALS['TL_DCA']['tl_metamodel_rendersetting']['metapalettes']
              );
          }
      }
docs: Build the data definition palettes.
  
  @param BuildDataDefinitionEvent $event The event.
  
  @return void
  
  @SuppressWarnings(PHPMD.Superglobals)
  @SuppressWarnings(PHPMD.CamelCaseVariableName)