In defining a hook_block_info() is it possible to define the region per theme? I'm trying to avoid this error and it seems I should be able to define the blocks region on a per theme basis. I've checked the API documentation but it's not covered. Has anyone pulled this off yet?

A for instance would be how do I additionally define the sidebar_first region in Bartik in the following example?

Here is my current _block_info():

  $blocks['find_activities_large'] = array(
  'info' =&gt; t('Find Activities Widget (large)'),
  'status' =&gt; TRUE,
  'theme' =&gt; 'MY_CUSTOM_THEME',
  'region' =&gt; 'inner_sidebar',
  'weight' =&gt; 0,
  'visibility' =&gt; BLOCK_VISIBILITY_LISTED,
  'pages' =&gt; '&lt;front&gt;',


);
I can't say for sure but I would be surprised if that works.

You could try to define the region using the Context module and Context Conditional Theme module if you only want certain blocks to show up in certain regions for certain themes. Context module configuration is exportable so you could commit those settings to code.