Why does my base template never reload? I use template inheritance:

In _layout.html every other template is loaded with {% block content %}{% endblock %}

The problem: _layout.html never reloads. I changed the CSS path in the head tag of _layout.html but I never see the change reflected. Why?


restarted MAMP (cache is already disabled)
restarted computer
emptied every cache I know of
cache tags aren't used
used all different browsers
deleted the storage/runtime folder


The above steps have no effect, and any changes on _layout.html don't appear to do anything. Why might this be?
Are you using PHP 5.5?  If so, opCache is enabled by default and that’s probably causing your issue.