Interactive selection of image subregions

I need the possibility to interactively select image subregions somewhere inside a workflow for further processing in the rest of the workflow.
A suitable solution would be an image viewer module that allows to outline image subregions using the mouse cursor. The output of this module would be the coordinates of the selected subregion(s).
Can the 2D/3D image result viewer be modified in that way, or do you have other sugggestions how this could be achieved?

Dear Heiko,
many thanks for your input. Currently our viewer is not capable in doing so. Easiest would be creating a cropping-/ ROI-module for such task. Unfortunately, we don’t have any yet. I forwarded your feature request to our team.