Use the new render mode in models and activate it in the panel

src/Cms/ModelWithContent.php

@@ -129,14 +129,25 @@ abstract protected function commit(
 	 */
 	public function content(string|null $languageCode = null): Content
 	{
+		// get the targeted language
+		$language = Language::ensure($languageCode);
+
+		// fetch a specific version in preview render mode
+		// @todo this entire block can be radically simplified as soon
+		// as the models use the versions exclusively.
+		if (VersionId::$render ?? null) {
+			$version = $this->version(VersionId::render($this));
+
+			if ($version->exists($language) === true) {
+				return $version->content($language);
+			}
+		}
+
 		// single language support
 		if ($this->kirby()->multilang() === false) {
-			return $this->content ??= $this->version()->content('default');
+			return $this->content ??= $this->version()->content($language);
 		}
 
-		// get the targeted language
-		$language = Language::ensure($languageCode);
-
 		// only fetch from cache for the current language
 		if ($languageCode === null && $this->content instanceof Content) {
 			return $this->content;

src/Panel/Page.php

@@ -4,6 +4,7 @@
 
 use Kirby\Cms\File as CmsFile;
 use Kirby\Cms\ModelWithContent;
+use Kirby\Content\VersionId;
 use Kirby\Filesystem\Asset;
 use Kirby\Panel\Ui\Buttons\ViewButtons;
 use Kirby\Toolkit\I18n;
@@ -373,11 +374,23 @@ public function view(): array
 	{
 		$page = $this->model;
 
-		return [
+		// This is placed here as a proof of concept
+		// @todo we need to find a better place for it
+		// to switch into changes mode in the panel
+		VersionId::$render = VersionId::changes();
+
+		$view = [
 			'breadcrumb' => $page->panel()->breadcrumb(),
 			'component'  => 'k-page-view',
 			'props'      => $this->props(),
 			'title'      => $page->title()->toString(),
 		];
+
+		// The render mode needs to be undone here to keep unit tests working
+		// That's the downside of such static properties. They are likely to
+		// cause side-effects
+		VersionId::$render = null;
+
+		return $view;
 	}
 }