Steps to reproduce:

1. Add some custom style/styles - https://doc.ibexa.co/en/latest/content_management/rich_text/extend_online_editor/#configure-custom-styles.
2. Create a new Article.
3. Apply custom style to selected text.

Result:
Even though in DOM custom style is properly applied, an indication is barely visible. The 'select' element doesn't update properly.

Expected result:
An indication should be more visible. The 'select' element should update after choosing a custom style.