In the app builder application, when applying a filter using the "is not" condition yields wrong results. It works exactly how "is" works. For example I have A and B entries in the field and I say filter this field and show what "IS NOT" A. It should show me only the B entries in the map but it does the opposite. If I try to use the condition "is" it again shows the A entries which is correct in this case. So "is" and "is not" yield the same results.
I tested it in the web map and it works correctly there, so I guess it is a problem with the web apps.
I see the issue you are mentioning. I was able to get it to work properly if I set Case sensitive in the Query widget setting for that expression. You should call esri tech support and log a bug for this.
It tells me I cannot use case sensitive in hosted features..
OK. So there is no workaround for you then. You need to report this immediately so it can be addressed in the next release.
I'm still curious because from what I understand from you first reply is that you managed to use filtering on a layer that was not hosted (since you used case sensitive option). But filtering does not work on non-hosted layers in the first place. Isn't that right? How did you do that?
I was able to filter an esri sample server service using the Case sensitive checkbox and the Is not operator.