Current Directory

For example,
In WordComplete Properties, browse and select the default dictionary file. (Note that this changes EmEditor’s Current Directory.)
Now the path in the box is:
C:\Program Files\EmEditor\Dictionaries\en_US.dic
Change it to relative path:
.\Dictionaries\en_US.dic
OK.

** But the relative path is not working since the Current Directory changed.
To make it work, you have to change back the Current Directory and disable+enable WordComplete, or restart EmEditor.

** Similar issues could happen in other path-related settings.