I just researched my \"bug\" and it turned out to be a new feature in Django 1.9 that CharFields strip spaces by default : https://docs.djangoproject.com/en/1.9/ref/forms/fi
Seems like the best way to handle this is to create a custom admin form like this:
class CustomForm(forms.ModelForm):
my_field = forms.CharField(strip=False, widget=forms.Textarea)
class Meta:
model = MyModel
exclude = []
This will create a default form with just my_field overwritten with its non stripped version. )this has to be set in the corresponding admin of course. If anybody knows an even simpler version. Please tell me!