HAProxy > Public Services > Select Rules > one rule is always missing

[t.mayer]

When I want to select rules for a public service (frontend), the dropdown always shows one rule less as i have defined in the rules section.
Example: When I have defined 9 rules in the rules-section, only 8 rules are shown in the select-rules-dropdown of a public service.

I  observed this behaviour on Firefox and Chromium.

Can you help me?
Greeds and Thanks!
Tom.