Removing the old IDEs dropped the startup time to 10seconds.
Not sure who is doing the QA on these 1.0 Beta releases, but they now have a lot of work to do.
Having all the IDE windows use the same board
better to allow different instances to have different run-time configurations.
Your design choice is either purposely limited (my next question would why!??!)
Are you sure you're both referring to the same situation:
My impression is that mellis is referring to "windows within a single IDE application instance" whereas BillO is referring to "multiple instances of the IDE application", is that impression correct?
In the Arduino world if there's a choice between making the common & beginner focused case easy; or, a more sophisticated case harder or impossible; then the choice will generally be made to choose the more limited beginner option, as Arduino is a beginner-focused platform.--Philip;