Why in Linux Mint + Double Commander txt file without text can't be opened by Enter?

Question

mint

I use Linux Mint and Double Commander.
- when creating an empty txt file (size - 0), it does not open when you press Enter,
- if you add, for example, 1-2 digits to the file and save - it does not open,
- a file of 4 digits, and even more so with text - opens .
Interested in two things:
- why so?
- can it be fixed?