The majority of Plone's theming machinery is built on Zope 2 and exposed though the ZMI in a tool called portal_skins
, at the root of every Plone site.
Inside portal_skins
are folders known as skin layers, additional places Plone will look for things. When a theme resource is needed for example, when an image is requested from the URL http://example.com/plonesite/folder1/folder2/image.jpg Zope looks for it in the following places in a predictable order, following a scheme called acquisition:
First, in
plonesite
→folder1
→folder2
→image.jpg
, just as the address says. If it is not found here, Zope continues on...In
plonesite
→folder1
→image.jpg
. Zope works its way up the chain of folders (called the acquisition chain), looking forimage.jpg
in each.In
plonesite
→image.jpg
.After Zope has searched the root of the Plone site, it takes a detour. It next searches each of the skin layers in order. However, it's not the alphabetical order listed on the main tab of
portal_skins...