'git gui' doesn't work in pair with 'git submodule foreach'

[skapral]

I'm trying to open git gui for each submodule in some Git repository. However, attempt to execute a command...

$ git submodule foreach 'git gui'

...fails with error message:

Tried out different workarounds, like setting path to submodule explicitly before calling git gui, but with no luck. The issue is reproduced only for git gui --- running gitk through submodules in the same manner works as expected. My environment is Linux Fedora latest, but the issue seems to be reproduced in Windows as well.