Messed up columns in Django Admin

In case this bites someone else like it bit more and chewed off many many minutes of debugging time.

If you ever get weird columns in your Django Administration interface, I now know why that happens. See this screenshot example:

This happens when you've defined a TEMPLATE_STRING_IF_INVALID in your settings.py. I always put in my local_settings.py this line:

TEMPLATE_STRING_IF_INVALID = '{{ %s }}'

So that I can quickly see which variable references in template code is potential typos. I'm not a big fan of the implicit magic of equating absence to False/None so I try to avoid the confusion altogether.