Caching issue - View's block without results

Problem:
If View with display 'block' is configured by blocktab, caching issue takes place if 'block' returns no results at some page.

Setup to reproduce:
- prepare View with 'block' display
- configure blocktab with View's block
- configure blocktab be visible at 2 pages: page1 and page2
- make sure View's logic (context arguments, view_query_alter etc.) returns rows for page1 and do not return any results for page2

Steps to reproduce:
- visit page1 - blocktab has content related to page1 context
- visit page2 - blocktab is empty, no content related to page2 context
- visit page1 again - blocktab is empty but should not
- flush views cache (or run function views_invalidate_cache) - blocktab has content related to page1 context again

Issues has been introduced with version beta1. It's not Views issue - you can configure the very same View's block next to blacktab to see it's fine.

Workaround:

In ViewsTab::getContent I have changed $tab_view = $view->render(); to $tab_view = views_embed_view($view_name, $view_display); just the way it was before beta1 and issue is not happening.