Pull Request for Issue # .

Summary of Changes

• Added the option to define custom classes for the image class dropdown in the TinyMCE plugin configuration, while keeping the default classes.
• When selecting "No Class Selected" in the image class dropdown, the class property is completely removed from the image.

Testing Instructions

1. Build the CSS.
2. Go to the TinyMCE plugin configuration.
3. Scroll to the bottom of the page to the Image Classes List parameter.
4. Click the green + symbol to add a custom class.
5. Add a custom class with name: myclass and value: myclass.
6. Go to an article and add an image.
7. Select the image and click the image icon in the editor icon bar.
8. Open the class dropdown and select the created class: myclass and click Save.
9. Open the Source Code Editor in TinyMCE and check if the class is in the image tag.
   
   
10. Open the image dialog again and remove the class by clicking: No Class Selected.
11. Check if the class property is removed from the image tag.

Actual result BEFORE applying this Pull Request

No classes can be added

Expected result AFTER applying this Pull Request

Classes can be added in the configuration and selected in the image class dropdown in TinyMCE

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed