Focus Window

1. Left, Right, Top, Bottom Window
You can switch to a window to the left, right, top, or bottom of the active window by pressing the hot keys (⌥⌘←, ⌥⌘→, ⌥⌘↑, ⌥⌘↓).
2. Highlight Left, Right, Top, Bottom Window
You can select one window from the windows located to the left, right, top, or bottom of the active window and switch to it by pressing the hot keys (⌥⇧⌘←, ⌥⇧⌘→, ⌥⇧⌘↑, ⌥⇧⌘↓). The selected window will be highlighted.
3. Preview Window
You can select one window from the windows on the desktop (such as windows not visible because they are covered by other windows) and switch to it by pressing the hot key (⌥⇧⌘↵). The selected window will be previewed.