Question 1: Is it possible to drag one box from grid1 and drop it into grid2?
Answer:
Sadly there is no such functionality available right now. Please have a look at this thread. https://github.com/tiberiuzuld/angular-gridster2/issues/245
Question 2: Are there other similar libraries for angular2/4 that support this?
Answer: Not sure about similar libraries implemented in Angular. However, I personally like gridstack.js
https://github.com/gridstack/gridstack.js
Mobile-friendly modern Typescript library for dashboard layout and
creation. Making a drag-and-drop, multi-column responsive dashboard
has never been easier. Has multiple bindings and works great with
React, Vue, Angular, Knockout.js, Ember, and others (see frameworks
section).
It supports the functionality that you needed.
https://gridstackjs.com/demo/two.html
There is no angular wrapper available for it. But you can directly use it in your angular project. To get you started I have also prepared one small stackblitz demo using gridstack.js with multiple grids.
Demo: https://stackblitz.com/edit/angular-ivy-mlnqah?file=src/app/gridstack/gridstack.component.ts