A window should not steal away focus until the mouse button is released after clicking on it.
Advantages of such a behaviour:
Imagine a situation when you drag and drop your videos to say, VLC. You have a maximized nautilus window at back and a smaller vlc window on it's front. When you click on the video to drag it and drop it, nautilus immediately steals the focus from vlc and vlc hides behind the maximized nautilus window. So you have to drag the icon the whole way to the task bar, hover over the vlc entry for a second while vlc gains back focus and comes forward over the nautilus window, and then drop it on the player window.
Suppose if a window is designed *not* to steal focus on mere clicking but only after the mouse button is released, the above mentioned situation could be easily handled :-
- If a user wishes to drag, so he might not release the mouse at all when he clicks on the nautilus window. So the focus will remain on vlc and the user could easily drop it on the player.
- If the user actually wants to switch the focus to nautilus from vlc, he would prefer *clicking* on the nautilus window to bring it to the front, and hence would be releasing the mouse button while doing so. That would naturally, bring nautilus to front giving it focus.
*** Not marking this to be related to nautilus as the scenario is same for dolphin also.
