Allow setting the summary of issue as a fixed part of the issue view

When viewing an issue that has a long thread of comments or entries of any kind it, and scrolling down, the issue summary and the issue key and hierarchy information also goes away. It would be useful to to be able to set this part of the issue as a kind of "header" which is fixed and stays visible even when scrolling down, in this way it would always be accessible and it would be easier to navigate back and forth through the issue hierarchy as well as keeping the context of which issue we are at the moment.