Merge branch 'master' into fix-2901

- Mod PreviewAction to prevent folders from being previewed;

src/ui/preview/PreviewAction.js

@@ -63,7 +63,7 @@ export default class PreviewAction {
         });
     }
     appliesTo(objectPath) {
-        return !this._isNavigatedObject(objectPath)
+        return !this._isNavigatedObject(objectPath) && !this._preventPreview(objectPath);
     }
     _isNavigatedObject(objectPath) {
         let targetObject = objectPath[0];
@@ -71,4 +71,8 @@ export default class PreviewAction {
         return targetObject.identifier.namespace === navigatedObject.identifier.namespace &&
             targetObject.identifier.key === navigatedObject.identifier.key;
     }
+    _preventPreview(objectPath) {
+        const noPreviewTypes = ['folder'];
+        return noPreviewTypes.includes(objectPath[0].type);
+    }
 }