Working on my AjaxNavigation product, I stumbled in a problem that a content provider which works happily all the time when used in my mainpage_view.pt refuses to work when used in the modified mainpage_embed.pt template (which is used for AJAX loading and doesn't use the main_template.pt.
The error occurs in the zope.contentprovider.tales module when the TALESProviderExpression.__call__ method tries to read the "view" from the econtext.vars - which is not present in this case.
Are there special circumstances necessary to have the tal:content="structure provider:plone.rightcolumn" work?
(Plone 4.3, I'm afraid; zope.contentprovider v3.7.2; both mainpage_view.pt and mainpage_embed.pt are from my myproduct_custom skin layer