Resume with uses existing activity instance even if a different activity is chosen

[quozl]

Reproducer: open Record, take a photo, switch to Journal, locate the photo, right-click, choose Resume with, and Image Viewer.

Expected result: Image Viewer activity starts and photo is shown.

Observed result: Record activity regains focus.

Workaround: stop Record activity before trying to Resume with.

(issue created so that anyone else can work on the problem)