When opening New regular expression input form, the user can see a Delimiter field label, but no field for delimiter input.
This is true for Expression Types where you cannot modify the delimiter.

Proposed options for the solution include, but are not limited to:

• to show a read-only dropdown with the default delimiter in these cases;
• to hide the Delimiter label if the delimiter is uneditable;
• other...

Steps to reproduce:

1. Go to Administration -> General -> Regular expressions -> New regular expression
2. If not yet selected, select Expression type = Character string included

Result:
There is a label for the field Delimiter, but no input field

Expected:
Clarification needed from Design team