Disabled cell still working if my event is longer on the right than disabled cells

You should check if you really disable the correct cells. The background color needs to be set separately so it's possible that you didn't disable all the colored cells. It's unlikely that the Scheduler will allow dropping the event on disabled cells.

If you believe that this is a DayPilot bug I'd need a sample that reproduces the issue.

the cells are disabled becouse if I move the event from left to right they are all disabled but when the event exceeds the disabled cells (only on the right as shown in the above screenshot) then I can drop the event.
It should be nice to have something to debug even from the browser console to see if there is a conflict or something that I can't see.
On the demo solution it works fine but everyone is using Daypilot in own custom projects and this may lead to conflicts that the developer can't see and should be nice to call some js function or something that could help us debug where the conflict comes from.

If you use libraries that modify built-in objects and/or their prototypes, like prototype.js, pretty much anything can happen. Try to use libraries that don't do that because it can cause conflicts with other libraries.

I recommend removing all other libraries temporarily to see if the problem disappears. Then try re-adding them one-by-one to see which one is causing the problem.

thanks a lot, I solved as you mentioned..removed one by one every js and found that even here prototype.js was the fault.
The "some" function was the problem. Since I need prototype I just renamed the function and the references to it and solved for now every bug.