Hello Mehmet,
MATLAB caches code so that it is able to run faster. Otherwise, every time you call a function, it would have to re-parse the text to know what to do. That's a fairly unsustainable model.
Generally, when you make changes to code, I'd recommend re-running the code anyway. It's a requirement in almost any other coding language that I can think of, because those languages compile the code into something machine-readable. MATLAB doesn't explicitly have a compilation step, but it still caches the instructions in a more compact manner.
If simply reopening the GUI doesn't work for you, you can also try clearing out class definitions. This is usually more applicable if you change something in a class definition, while you have an object of that class instantiated. To do this, run:
clear classes
You may need to rehash the cache to get the updated files. First try simply:
rehash
If that doesn't do it, go for the full:
rehash toolboxcache
Finally, there's always the option to close and open MATLAB. If that still doesn't catch the changed definition, then you likely have an older copy of that file somewhere higher on the MATLAB path.
You may be able to keep the GUI open and use clear classes or rehash without issue. You're welcome to try it, but I usually close and rerun the GUI just to be safe.
-Cam
