Each field can have a help text, which is configured in the field definition. 

1. If no help text exists, no indication for it exists. 
2. If a help text exists, a (i) indicator is shown below the field
3. The help text can be wysywig, so it's formatted. 
4. The wysiwyg text is sanitized so no <script> or onclick="..." may work
5. The initial text shown is only one line tall, followed by an ellipsis. 
6. Any click on the help text (the whole line) shows the full help text
7. When the help text expands, the (i) button becomes a (-) button to hide the text again
8. Clicking on the expanded help text does not hide it again, because we must ensure that
   1. Links in the help text can be clicked
   2. Users can copy text from the help-text