When you open a lot of windows, it clutters the F3 menu, especially if they are in fullscreen.
Now imagine all the windows with different content. It's very messy.
Also, you may not just be using Orion. The more apps you have in fullscreen, the messier it gets. Navigating by swipe would, at that point, become unrealistic.
A suggestion is to have a way to "hide" windows. A way this could be done is just to have the new window that you're switching to replace the old one, so you just have one window. Comake is a great inspiration for this.
It would be even greater if you can somehow keep the tabs in "hidden" windows loaded, so, for example, if I am playing music in a tab in a window and switch to another one, it still plays. This is a big downside of Comake as it removes the tabs and replaces them, which unloads all tabs.
