Fix global styles duotone not rendering in post editor

src/wp-includes/block-supports/duotone.php

@@ -584,21 +584,3 @@ static function () use ( $filter_svg, $selector ) {
 	)
 );
 add_filter( 'render_block', 'wp_render_duotone_support', 10, 2 );
-
-/**
- * Render the SVG filters supplied by theme.json.
- *
- * Note that this doesn't render the per-block user-defined
- * filters which are handled by wp_render_duotone_support,
- * but it should be rendered in the same location as those to satisfy
- * Safari's rendering quirks.
- *
- * @since 5.9.1
- */
-function wp_global_styles_render_svg_filters() {
-	$filters = wp_get_global_styles_svg_filters();
-	if ( ! empty( $filters ) ) {
-		echo $filters;
-	}
-}
-add_action( 'wp_body_open', 'wp_global_styles_render_svg_filters' );

src/wp-includes/default-filters.php

@@ -574,6 +574,10 @@
 add_action( 'wp_enqueue_scripts', 'wp_enqueue_global_styles' );
 add_action( 'wp_footer', 'wp_enqueue_global_styles', 1 );
 
+// SVG filters like duotone have to be loaded at the beginning of the body in both admin and the front-end.
+add_action( 'wp_body_open', 'wp_global_styles_render_svg_filters' );
+add_action( 'in_admin_header', 'wp_global_styles_render_svg_filters' );
+
 add_action( 'wp_default_styles', 'wp_default_styles' );
 add_filter( 'style_loader_src', 'wp_style_loader_src', 10, 2 );
 

src/wp-includes/script-loader.php

@@ -2336,6 +2336,34 @@ function wp_enqueue_global_styles() {
 	wp_enqueue_style( 'global-styles' );
 }
 
+/**
+ * Render the SVG filters supplied by theme.json.
+ *
+ * Note that this doesn't render the per-block user-defined
+ * filters which are handled by wp_render_duotone_support,
+ * but it should be rendered before the filtered content
+ * in the body to satisfy Safari's rendering quirks.
+ *
+ * @since 5.9.1
+ */
+function wp_global_styles_render_svg_filters() {
+	/*
+	 * When calling via the in_admin_header action, we only want to render the
+	 * SVGs on block editor pages.
+	 */
+	if (
+		is_admin() &&
+		! get_current_screen()->is_block_editor()
+	) {
+		return;
+	}
+
+	$filters = wp_get_global_styles_svg_filters();
+	if ( ! empty( $filters ) ) {
+		echo $filters;
+	}
+}
+
 /**
  * Checks if the editor scripts and styles for all registered block types
  * should be enqueued on the current screen.