The Changes panel (Alt+F9) contains tabs Local, Repository and Incoming. In the tab Local you can use feature "Jump to Source" (F4). This feature is missing in Repository (and possibly Incoming) tab in the Changed files pane. I think it should be possible to press F4 to display the file in editor for the convenience. One more reason to add this feature is that the button Show History in the Changed files pane is enabled only if the file is displayed in editor.