Hi
I'm not sure why exactly it happens. Does it happen after you publish your mod?
Anyway, as a small solution you can try
1. close the editor
2. go to EE files, find you mod
3. right click on it's folder, select Properties (I think it's properties in the english windows, but not sure)
4. Take a look at Read Only attribute, if it's checked - unckeck it and hit OK