Trigger was removed from core for D8 without providing a worthy alternative other than Rules (which by many is considered a "cumbersome piece of code with a confusing UI"). Having in mind our goals to be providing as much backwards compatibility as possible and easier transition from D7 to Backdrop, should we consider bringing trigger.module back in Backdrop core ...or at least putting it in contrib as a "lightweight" alternative to Rules (which is not fully ported yet and might take time to do so)?
For the record, here's a summary of the reasons for it's removal from D8 core (from the respective issue in the d.org issue queue: Remove Trigger module from core [#764558]):
The actions API is wonky (look up your action via hash of function name?), actions/trigger has no maintainer in MAINTAINERS.txt and we have not seen the promised conversion of things like node operations into actions.
Also, the trigger UI is weak, and there's not a lot you can do with it.
In general, people use a contrib module like Rules - so let's just put this code back in contrib where it belongs and reduce some of the bloat in core.
Recent comments
Glad it works for you! Regarding selecting options, I've just tested the Views Autocomplete Filters module and got it working after I had a look at the README and made sure to use the same...
Can't filter content in a View
You are right, that was it... Now my problem is I would like users being able to select from pre-established options, like a drop down or maybe an autocomplete. For that I would the Autocomplete...
Can't filter content in a View
Here goes the screenshot for the exposed filter config I will try the module you are telling me about. thanks again!
Can't filter content in a View