Multiple Window Option
Currently, a new window will open every time you click the appropriate button.
For v1.9, clicking the button will only open a window if none exist. Otherwise, it will bring the current window to the front.
If you shift-click the button, it will open a new window regardless of how many are currently open.
The following windows may only have ever have one instance open:
Create Project
Missile Design
Turret Design
The Medals Window is a dialog window so retains focus while it is open.