Right now getElementsByTagName is used to fetch element's ezconfig. This kind config is used in different cases:

• custom attributes
• embed/custom tags parameters

Right now strange results sometimes are shown In cases when there are multiple nested elements with ezconfig. It happens because getElementsByTagName returns random (first?) ezconfig element. Instead, the first-level child ezconfig should be returned. 

1. Setup 2 custom tags: custom_a and custom_b. Both of them need to have own parameters set.
2. Start to edit any content with Rich Text field.
3. Add custom_a tag to any Richt Text field and set its parameters.
4. Add custom_b tag Inside custom_a. Set some parameters for custom_b.
5. Save the changes.
6. Open the edited content on the front-end, and params of the nested custom tag (#4) will be used to render the parent custom tag (#3).