The framework - set of internal libraries, will be open sourced.
I'm not sure that such change will be as significant as you describe. The 4 IDEs actually share 90% of the code between them and the IDE is small enough that it is not a big deal to have 4 copies of it.
I tried to "paste" some views "copied" from Designer (selecting them all and pressing CTRL+C) to a text editor, without success, so the Windows Clipboard does not contain text.
Will be "shared" (open source) this too? Can I manage it some way even now (as well as being able to copy them in another designer - or in another layout, which of course already feasible now)?