I'm testing page_manager on a fresh install of Drupal 8 (V 8.1.8).
I installed :
Layout Plugin 8.x-1.0-alpha22
Page Manager 8.x-1.0-alpha24 (with page_manager_ui)
When I try to create a Panel variant in a custom page, I've got no option to insert a block...
My UI appears like that :
Where can I add content in this page ?