Steps to reproduce:

1. Create a Form and add a button to it.
2. Choose "Show a message" in the "Action" select.
3. Notice the * in the label.
4. Do not enter anything there, just click on the "Submit" button.

Result:
The button configuration was saved.

Expected result:
There should be a validation error present as the "Message" field is supposed to be required.

Note:
This is the same case for any field and their name field.