The styling for the Views bulk action form is limited and can lead to confusion when presented along side other form elements. For example, on the administration content listing page (/admin/content) the bulk action form is presented beneath the exposed filter form and confusion can exist between the fields and apply buttons for the two forms.
Add a wrapper mechanism and some simple block styles to the bulk action form wherever it appears in the Seven theme (both for views bulk operations and hardcoded bulk operations like the comment list).
Maybe in the future
An enhanced version is possible that 'joins' the Views table header visually with the bulk action form, adding an additional pointer arrow to the 'select' checkbox column. This approach would not work when the View doesn't use a table display, so we discarded this for now.
User interface changes
Change of Views bulk action form styling background and border, see proposed resolution.
No changes. Adding #bulk_operations element.
Data model changes