Initially I implemented it that way, the problem is that people kept pressing outside the window, making the window lose focus.. At the end I decided to disable fire by mouse click, once you get used to it I don't think it's uncomfortable or anything. My guess is that people have a problem with it mostly because they are used to fire by mouse click used in other breakout like games.

The alternative is to "steal" the mouse cursor, but I'm a little afraid that may confuse some users even more. Maybe I should ask what the usability people think about it.

this should be a config option.
unfortunately the shortcut dialog doesn't seem to accept a "click".

You don't want to be able to use a mouse click without the window "stealing" the mouse, you continually click on other windows making them get focus. It was this way before and I assure you it's very annoying.

For the next version (KDE 4.2) however I plan to add an option [ ] "mouse stealing + fire on click", disabled by default.

with gnome-breakout i had the cursor visible and the game paused when it leaves the window (that was configurable). a visible cursor also help with aiming.

I would argue that the user is responsible for making sure the mouse does not leave the window (full screen, etc).

Yet, both mouse stealing _and_ the 'pause on cursor leaving window' thing should be offered. That way, people can use their preferred mechanism.

Well Murphy's law says that people _will_ click outside the window eventually. And when in the beta versions fire-by-click was enabled when I let people try the game it happened a lot, and even sometimes it happened when playing myself. 
I'm convinced it's best to keep the default as it is and adding an option to fire on click, which would steal the mouse (until you pause the game, pressing Esc will also pause the game).
I think that once you know that it's enough to pause the game to get the mouse cursor back the second method is best. But I can't think of a good way to make sure the user knows that, so I will write it near the option: if they enable the option they will know.

let the user know that

SVN commit 938613 by fela:

Added option to enable fire on mouse click, default is off, if the user tries to 
use the mouse to fire the ball a dialog will ask him if he want to enable fire on 
mouse click, warning him that this way the mouse cursor will be stealed.
BUG:162528


 M  +7 -4      TODO  
 M  +3 -0      src/CMakeLists.txt  
 M  +22 -7     src/canvaswidget.cpp  
 M  +6 -2      src/canvaswidget.h  
 M  +4 -1      src/gameengine.cpp  
 M  +3 -2      src/gameengine.h  
 A             src/generalsettings.ui  
 M  +4 -0      src/kbreakout.kcfg  
 M  +1 -1      src/main.cpp  
 M  +73 -9     src/mainwindow.cpp  
 M  +1 -1      src/settings.kcfgc  


WebSVN link: http://websvn.kde.org/?view=rev&revision=938613