The plugin works fine in Firefox, but does not work in Internet Explorer and Internet Explorer (64-bit).
Internet Explorer status:
The arrow and title are shown, but when clicking the link to expand nothing happens. Then on reload all content is exposed (not collapsing).
Internet Explorer (64-bit) status:
All content in the [expand] shortcode is displayed on the page, but is not collapsed - fully viewable. (e.g. Dropdown arrow shows along with the title and content below exposed)