I am unable to edit or delete a Schedule Helper. Any suggestion is welcome 
First of all Threads of “i am unable to xyz” are not very helpful and people wont really help you because it is low effort and way too vague and does not motivate people to help you.
Read this first before doing anything:
What have you tried? What Errors do you encounter? Why are you unable?
I Assume you created one via the “Helpers” Section?
If yes:
- Go to the Helpers section: ip.of.your.homeassistant:8123/config/helpers (not developer tools, because it seems to not show you all you want)
- Identify your Schedule
- Select your Schedule (click on it) it will show a history stats window of the entity
- Select the cog on top right corner of the History Stat-Window of the schedule that you have opened. It will now show you a “calendar”. Change the schedule on how you want to.
If no:
ask a better question
Hello that doesn’t work for me, I will edit the Schedule in the Helpers Section.
I open the History window and click on every thing if its clickable 
but there no calendar.
THX for Feedback
a liitle longer investigate… i will link to the solution. So if another one comes here. He can go straight there
just saw that i have the same issue. cand edit a schedule
I had the same issue and believe it is due to a browser plugin. In my default profile, the calender never shows up, but if I open it in a guest/incognito profile the calendar appears. Not sure which plugin is at fault, but at least I can edit my schedules now!
Same issue here. Doesn’t show up in safari, but works fine in the (iOS) app.