Hi Santi Peralta
What kind of development environment do you have set up? Are you running a local copy of Tiki intended for developers to test this? I'm not sure all the caching options in Tiki but know there are settings that can drive a developer nuts. Such as JS minification.
I did a quick search for duplicate function names, and there is none.
(I know its dumb) but I've sometimes found myself in the wrong branch of Tiki, trying to view changes that I made on another.
When you view the source code or inline DOM viewer does it also do the same thing? How about when you make the changes directly into your DOM viewer?
Make sure you're actually saving your file, and it's being saved in the right location (another dumb one again, I know)
In the browsers, I use the force refresh is generally shift (while hitting the refresh button) that's an important feature. But you can also view what resources were re-downloaded by viewing the "network tab" in the DOM viewer.
Most of us working on Tiki are using the PhpStorm editor. It might help remove some possible errors, for example, it has inline error checking and auto-saves as you type. Its a great editor. I don't do much JS coding but know it does have JS functionality as well.
Hope some of these ideas might help, or at the very least are things to consider or eliminate as possible causes of the issue.
Happy to help more if I know a little more about how you're going about this task.