When editing a global parameter, the "Hidden value" checkbox doesn't replace the full editor (added in #11625) when checked, and the new textbox stays there when unchecked.

1. Edit a non-hidden parameter, check the "Hidden value" box and a new textbox appears between the editor toolbar and textarea. The old non-hidden value is still shown in the textarea.

2. Untick the "Hidden value" box and the new textbox remains.

3. Create a hidden parameter, untick the "Hidden value" box and the password field is replaced by a textbox and not the editor.