I'm unable to duplicate this on master. I tried emptying the field and then deleting it, which worked. I also tried adding an empty field in wikitext, saving, and then opening it up in VE. I was able to delete the parameter then too.

Do you have any more details that might help us duplicate? Do you have a particular diff where this was happening?

I tried to delete the field on [https://it.wikipedia.org/wiki/Atletica_leggera_ai_Giochi_della_XXV_Olimpiade_-_100_metri_ostacoli this page] with Chrome and Firefox, but I couldn't delete any field.

In [https://it.wikipedia.org/w/index.php?title=Utente%3ANnvu%2FSandbox1&diff=69043230&oldid=69043213 this edit] I tried to delete the field "successivo" (which is not a required field) and I couldn't delete it.

Ok, on both of those templates I was able to delete the missing fields while using Chrome on Ubuntu.

You could try opening up the javascript console in Chrome (Ctrl+Shift+J) and seeing if any errors appear when you try to use the bin button.

I got no error.

Could not confirm - tried both mentioned links - [https://it.wikipedia.org/wiki/Atletica_leggera_ai_Giochi_della_XXV_Olimpiade_-_100_metri_ostacoli] and[https://it.wikipedia.org/w/index.php?title=Utente%3ANnvu%2FSandbox1&diff=69043230&oldid=69043213]
any field(empty or not) can be deleted.

Can confirm in Chrome and FF. What happens is that clicking on the bin makes the field disappear in the dialog, but when you save it's still in the template, as if you hadn't changed anything.

Did we break something when we re-wrote the template parameter fixing code last week?

gerritadmin wrote:

Change 172317 had a related patch set uploaded by Catrope:
Followup a054a75: don't reintroduce removed template parameters

https://gerrit.wikimedia.org/r/172317

gerritadmin wrote:

Change 172317 merged by jenkins-bot:
Followup a054a75: don't reintroduce removed template parameters

https://gerrit.wikimedia.org/r/172317

gerritadmin wrote:

Change 172446 had a related patch set uploaded by Catrope:
Followup a054a75: don't reintroduce removed template parameters

https://gerrit.wikimedia.org/r/172446

gerritadmin wrote:

Change 172446 merged by jenkins-bot:
Followup a054a75: don't reintroduce removed template parameters

https://gerrit.wikimedia.org/r/172446

Fix was backported to wmf7 and deployed.

Verified in Betalabs and test2.

Confirmed, it works on itwiki (Chrome; VEctor; Win 8.1)

Verified in production.