The window that is "in focus" receives keyboard input and has the active titlebar appearance (usually colored instead of gray). The focus can be switched to another window with the keyboard (Alt+Tab) or the mouse. The Focus policy determines which window is in focus at a given time. When the focus policy follows the KDE style, the Alt+Tab key combination allows the focus to be transferred between windows on a graphical listing of the open windows.
If click to focus (KDE style) is selected, the user must click the mouse inside a window to raise it to the front and give it the focus.
If Focus follows mouse (KDE style) is selected, the focus switches to a window as soon as the pointer enters it. This makes focus switching without raising a window easier, but with the disadvantage that the position of the pointer is important even when the pointer isn't being used. The window remains in focus until the mouse pointer enters another window, to which focus then passes, so some window is always in focus.
The Classic sloppy focus policy is similar to the "Focus follows mouse" policy, except that the action of the Alt+Tab key combination switches the focus directly between windows in the CDE desktop style, rather than in the graphical KDE style.
The Classic focus follows mouse policy is a similar CDE-style policy, except that the window loses focus as soon as the mouse pointer leaves it. If the mouse pointer is not in any window, (for example, is on the desktop background or Panel), no window is in focus.
Selection of the Auto Raise feature serves to raise a window to the front (top) when it gets the focus. If a delay in milliseconds is set using the slider control, the window is only raised if the mouse is still inside the window after a period equal to this delay has elapsed since focus passed to it. (This does not apply when the "click to focus" policy is in force).
Selection of the Click Raise feature allows a window to be raised to the front by clicking the mouse anywhere inside it. If this feature is not selected, only a click on a window's titlebar will raise it to the front. (This does not apply when the "click to focus" policy is in force).