1. Create content type with richtext and two other fields, all required.
2. Go to create content item with content type from previous step
3. Don't fill anything, just click publish - validation alert is shown for all fields except for richtext. When the two fields are filled and you will click publish, then validation alert will be show for richtext. The exclamation mark is moved a little and there is a little inconsistency with validation message - for the other field there is ".... field is required"