Thank you!
Valid point and taken...
I've seen the menu what, but were not sure where the help files live. After adding the help files I found in the UE folder nothing happens when I press F1.
Should I restart UE?
There is normally only 1 help file - Uedit32.hlp (< V10.20) oder Uedit32.chm (>= V10.20) - and this help file is built in at UE - see Help - Index or hotkey F1.
The feature of adding user help files is normally used for adding programmers help of third party tools. I add the help of my compiler and assembler for example. So I can select a word and press the hotkey for the appropriate user help file and UltraEdit opens the help file and shows me the help about this word, if the word is in the index list of the user help file.
Hotkeys to user help files can be assigned in the Advanced - Configuration - Key Mapping dialog, entry HelpUserFile
Best regards from an UC/UE/UES for Windows user from Austria