Originally something that I made for ACT's HTML exports, I thought I would share it to a broader audience if it was useful to anyone. No fancy bookmarks, just very little wasted space.

When Title/Frame settings are set to hidden in the Window Settings, the browser area takes up about 95-99% of the window. The URL bar/controls are an overlay that auto-collapse if the mouse moves off of it. Pressing the "+" button in the upper left corner will re-show the URL overlay. The window also has a "^" button which collapses the entire window into a button about 16x16. When collapsed the browser doesn't apply a FPS performance hit. So it's an alternative to closing the window and losing your open URL.