dict – file not found
I've been experiencing a lot of strange behaviour when reading files: it almost never works when I just pass the filename of a file that is right in the patcher's folder. So I was specifying the path explicitly through the [thispatcher] object. But now even that doesn't work with the [dict] object. Reading/importing it through the dialogue window works.

If the file extension is *.json it works fine. Still strange that *.txt works from open file dialogue but not with messages.
json is plain text, but dict expects extension that it can cope with,
or better say is written using acceptable syntax.
If you export dict file using all available file format options,
you will see that only yaml differs, no brackets and treating symbols differently.
All others are same.
if you want to read or import files with .txt extension using messages,
use regexp set to replace .txt with .json.
if file is properly formatted it will be accepted, otherwise not.

you could also mess with max-fileformats.txt file in init folder
to make dict directly accept txt file...
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Why that difference between message and read dialog ?
remains one of many mysteries in max, maybe to help one not get bored
with stuff that allways work as one would expect it to...
Like try to force open dialog to accept only midi files
which are binary .mid format, ignoring TEXT formated ones ....
Thanks for the suggestion and clarification! Anyways it's not a problem for me to give a file another extension on creation.