diff --git a/packages/block-editor/src/store/private-selectors.js b/packages/block-editor/src/store/private-selectors.js
index c46778d889b3e0..72b87a59e8f571 100644
--- a/packages/block-editor/src/store/private-selectors.js
+++ b/packages/block-editor/src/store/private-selectors.js
@@ -502,13 +502,23 @@ export const getParentSectionBlock = ( state, clientId ) => {
  * @return {boolean} Whether the block is a content locking parent.
  */
 export function isSectionBlock( state, clientId ) {
+	const blockName = getBlockName( state, clientId );
+	if (
+		blockName === 'core/block' ||
+		getTemplateLock( state, clientId ) === 'contentOnly'
+	) {
+		return true;
+	}
+
+	// Template parts become sections in navigation mode.
+	const _isNavigationMode = isNavigationMode( state );
+	if ( _isNavigationMode && blockName === 'core/template-part' ) {
+		return true;
+	}
+
 	const sectionRootClientId = getSectionRootClientId( state );
 	const sectionClientIds = getBlockOrder( state, sectionRootClientId );
-	return (
-		getBlockName( state, clientId ) === 'core/block' ||
-		getTemplateLock( state, clientId ) === 'contentOnly' ||
-		( isNavigationMode( state ) && sectionClientIds.includes( clientId ) )
-	);
+	return _isNavigationMode && sectionClientIds.includes( clientId );
 }
 
 /**