Calling share_attribute_with_element() does not
immediately update the to-element's attribute. If you would
like that to happen, call update_shared_elements()
To disable the background, set the background_disabled
attribute to true. To disable the border, set the
thickness attribute to 0
SVG: Look into multi-color support via referencing element ID's
from within the theme tags
Ensure that buttons have adequate padding by default, as well
as support for padding adjustments.