How to find in which folder / app group is an app icon? I honestly feel stupid asking this question, but here it goes:
I cannot find a way to locate in which folder/app_group I misplaced an app icon.
If I use the search in the app drawer (go-Launcher Z or default home screen app (TouchWiz home), I can easily find the app icon, but it will not let me know in which folder/app_group the icon is.
On IOS you can achieve this very easily:
If you searched for an app, you will see an app icon—which you can tap to launch the program—as well as a header that tells you in which folder the app is stored.
This is a search example (for the Netflix icon/app):
 
You can see that the icon is located in the media folder. In this case it is easy to find, but when a folder holds more than 4 icons locating an icon is tedious.
 
GALAXY S6
Android 7.0
If you search in apps, locate the icon in the results and then press and hold on that button you will get a short pop-up menu which includes "Locate" that does the job nicely, (not sure which version introduced this feature).