Pick rectangle from existing windows

[ewerybody]

All tools have this already. Should be easy to do 👍
What I'd love additionally: shrink or increase the size of the rectangle with easy modifiers.:

scroll wheel:

• outside the drawn rectangle: move edge or whole box
• inside the rect: grow/shrink
• 10x the pixels with Shift key

[ewerybody]

The picking thing is a bit tricky it seems. There is pygetwindow but it gets a lot of windows and we'd need to filter first. I don't know yet if the order is correct. Maybe we need an Autohotkey hack? :/