1. Have a template in ~/Templates
2. Right click in a directory, select create document, select the template
3. Press enter without changing the default document name.
4. Do step 2 and 3 again.

The second document created will have the wrong extension because of Nautilus
way of naming duplicates. I.g if the template is called "python.py" the second
will be called "python.py 1" and then "python.py 2" and so on.

It would be much better if the duplicates was called "python (1).py", "python
(2).py" or something like that, because then they wouldn't get the wrong extension.