Can't enter unicode character with Alt+ even with EnableHexNumpad

I'm trying to enter unicode characters by using Alt+#### but I'm not being able to.

In Registry Editor, I added a new String value called EnableHexNumpad with value of 1 in HKCU\Control Panel\Input Method and rebooted, but nothing has changed. What's happening?

I'm using Window 8.1, tried on Word, Notepad, Chrome, Visual Studio, nothing...

Any clue? Thanks in advance!

edit:

reg query "HKCU\Control Panel\Input Method"

output:

HKEY_CURRENT_USER\Control Panel\Input Method
Show Status        REG_SZ    1
EnableHexNumpad    REG_SZ    1

HKEY_CURRENT_USER\Control Panel\Input Method\Hot Keys

Edit: It was PEBKAC!
I was trying to type stuff like Alt+2075 (✅) without actually typing plus! Thanks to @JosefZ for clarifying this out for me.

To improve discoverability, I'm going to copy JosefZ's comment from more than a year ago into an answer:

With this registry settings: what happens if you type e.g. +03b1 while holding the Alt key? Greek Small Letter Alpha α (note that leading + is important while leading zeroes are not. So Alt + +3b1 is the same as Alt + +03b1

The registry setting in question is

HKCU\Control Panel\Input Method

which can be obtained from the command line by typing:

reg query "HKCU\Control Panel\Input Method"