Created attachment 1866344 [details]
Demo how to reproduce the bug

Description of problem:
Unable to add a vpnc connection.


Version-Release number of selected component (if applicable):
NetworkManager-vpnc.x86_64          1:1.2.8-1.fc36             @updates-testing                  
NetworkManager-vpnc-gnome.x86_64    1:1.2.8-1.fc36             @updates-testing                  
vpnc.x86_64                         0.5.3-43.svn550.fc36       @fedora                           
vpnc-script.noarch                  20201205-4.gitcdbd5b.fc36  @fedora 

How reproducible:
Every time

Steps to Reproduce:
1. Open Networks Settings
2. Add VPN (plus button)
3. Choose Cisco Compatible VPN (vpnc)
4. Fill out "Gateway"
5. Fill out "User name"
6. Write a single letter in "Group name" (or paste a whole string)
7. See the "Add" button become active
8a. Change a single character in "Group name"...
8b. or open "Advanced..." modal and close it again.


Actual results:
The "Add" button becomes inactive and never becomes active again.


Expected results:
The "Add" button stays active until the form fields are "invalid"


Additional info:
Workaround is to fill "Group name" last.