Preview Helpers for Small Structure Selection

### Problem

Currently it is difficult see the color that would be selected before clicking. This is a problem when selecting the color of very small structures. A lot of interfaces do not have an easily accessible zoom functionality.

### Proposal

These would be kind of 2 Feature requests, but both addressing the same problem:

1. A preview that updates the current color under the cursor while moving (without clicking).
2. A small but magnified regional preview of the cursor surroundings.

Anyway thanks for the work you've put into this already!

### Prior Art (Optional)

I found somewhat of an example here on the bottom of the page: https://www.officeoneonline.com/protools/color_picker.html on the bottom.