ROI selection

Hello, I really need help, so I have an image in which I must randomly select 50 cell nuclei, I already have all the image nuclei in my ROI manager, and I only want to select 50 of those, how can I do it?

Start with issue #229 and inspect ImageJ's ROI Manager selection behavior; the issue names no source file, test, or entry point. Clarify the intended random-selection workflow and identify the relevant ROI Manager code before implementation; done should mean selecting exactly 50 existing nuclei ROIs reproducibly or as specified.

Written by the indexing model from the issue text.