Viewing fields
A popup will show if you hover a URL of an issue for more than 0.5 seconds. After leaving the popup, it will disappear in a short time.
The hover is scroll-able and re-sizeable, so you can view as many fields as you want.
This functionality is enabled in Confluence pages, blog posts, comments and more.
Issue previews are possible in Jira and Bamboo also! See Issue Preview for Jira user guide and Issue Preview for Bamboo user guide