Regression: Cannot add/remove dashboard blocks to default dashboard. (master)

As an admin user Go to Site administration > Appearance > Default Dashboard page and turn "Blocks editing on" (button in top right). CHECK that you can Delete and re-add the timeline block to the page (Timeline will normally show by default.) If the Timeline block exists on the page (default) press the cog on the timeline block and make sure the option to "Delete timeline block" is available and it deletes as requested. Re-add the block back to the page by using the "add a block" link to add the Timeline block back to the course. Test that you can add a new "HTML block" to the page and then delete it. Go to a course page and make sure editing is still on, then check to make sure that the "timeline" block is not available to add as a block to the page. As a student user Log in and view the My dashboard page (/my). Hit the "Customise this page" button in top right. CHECK that the Timeline block can be added and removed like the above test on the default dashboard page. CHECK that you can also add and remove an HTML block on the page.