Hidden Notes/Comments

When I say smallish and larger below, I am not referring to font size. I am referring to a few visible words, plus a lot more words hidden.

I would like the ability to have a smallish text on the screen, and have much larger text associated with that smallish text.
If one mouses over the smallish text, you can see the larger test.
If you click an icon(or whatever), you can view and edit the larger text

I attempted to find flow charting software with no success.
I have checked out a couple of mind managers, which do have that ability, but they have other disadvantages. EG xMind has fairly rigid constraints on the related ‘shapes’.
I like the sound of Scapple, and would love it, if it had that extra ability.