Hi Levoca
The report that is shown when All appraisals is selected from the Performance top menu is an embedded report based on the Appraisal Status report.
If you create a report based on the Appraisal Status report and create a filter for Appraisal status is not equal to 'Closed' and also show Content by user then this will display Appraisal that are not closed for a user.
This can be added to the main menu as a report table block
Hopefully this will help you to get what you want to display.