You can use the JIRA toggle sidebar in JExcel.

You can open and close it 2 ways:

• by clicking on the icon  (1)
• with the shortcut F4

The sidebar itself is better organized and more responsive to size changing than the original one. 

In the sidebar menu, you can:

• resize the dialog 
• see the core information of the issue (2)
• see the description of the issue (3)
• see the attachments (4)
• see the time tracking of the issue (5)
• see the comments of the issue (6)