There are 2 ways to delete Supporting Documents after uploading them. Both are done after submitting the application, but before submitting Supporting Docs.
You can remove them completely from an application or remove them from a specific Supporting Documents requirement.
Remove completely from application
Select the document in panel 1
Press Delete in the top ribbon
You will then be asked to confirm and delete the file
Remove from a specific Supporting Documents requirement
Select the task from Panel 4
Select the document/s you want to delete in Panel 4
Press Delete in the top ribbon
You will be asked to confirm and delete the attachment/s
