How to make url attachments on workflow action page open in new window

Summary:

When a user clicks on an Account Coding workflow notification from the Bell icon list it takes them to the workflow task window which has a url attachment for the invoice pdf. If they click the url attachment it opens it in the existing window replacing the workflow coding actions and they cannot get back to the actions page without going to their worklist. They need the pdf open while they are performing the coding so we would like it to open in a separate window. See screen shots below. Is there a way to customize