cache a browser window on close (hide instead) to make next browser window fast. this is the same fix as #104989 (which is for the msg compose window) but applied to browser.

An early version of Bill Law's quicklaunch code (bug 75599) did something like this, but only for the first browser window. The problems he encountered with caching windows included: * bug 81708, the hidden window would get/keep focus and eat keyboard events * bug 81712, -turbo mode should not preload homepage * bug 82804, window state not persistent in -turbo mode * bug 83569, clicking links in mail doesn't work in -turbo mode Btw, I think Internet Explorer does something like this. IE always seems to open windows faster after I've been using it for a while.

This doesn't really seem like a great idea... given that many people have a single window with many tabs, they're not opening & closing browser windows. Dead for 7 years, and not going anywhere => WONTFIX