Automatic activation of tel: protocol association to an application

Hello Community

I modified the policies.json and added the 3CXDesktopApp application run with the tel: protocol.

“policies”: {
“Handlers”: {
“schemes”: {
“tel”: {
“action”: “useHelperApp”,
“handlers”: [{
“name”: “3CXDesktopApp”,
“path”: “C:\Program Files\3CXDesktopApp\3CXDesktopApp.exe”
“Certificates”: {
“ImportEnterpriseRoots”: true

The association works but on firefox it is not enabled as standard.
When I click on a page that has as example a link with a phone number such: +123456789 or whatever, firefox opens a popup window to allow the site to open the link

After clicking on Choose Application, a second popup is displayed.
Here I have to click "Always use this application to open tel links.

So this is a manual interaction of the user. I want to set these settings on configuration files, so that they are set automatically and no interaction from the user is needed.

Can someone help me to solve this issue? Where can I configure these settings? It seem to be a firefox specific issue. Or it’s possible to set these settings on the registry?