by opening the theme to edit, you are creating a new version in thethemes/temp_editing folder. the existence of the new version in the themes/temp_editing folder generates that warning.
If you have suggestions for new features or changes that you would like to see implemented, please post to the wishlist forum.
There will be an update to power store made available soon that will address the permissions issues, we are in the process of QA testing on it right now.