Massive Quartz input enhancements from Darrell Walisser. His email: Enclosed is a patch that addresses the following: --Various minor cleanups. Removed dead/obsolete code, made some style cleanups --Mouse Events Now keep track of what button(s) were pressed so we know when to send the mouse up event. This fixes the case where the mouse is dragged outside of the game window and released (in which case we want to send the mouse up event even though the mouse is outside the game window). --Input Grabbing Here is my take on the grabbing situation, which is the basis for the new implementation. There are 3 grab states, ungrabbed (UG), visible (VG), and invisible (IG). Both VG and IG keep the mouse constrained to the window and produce relative motion events. In VG the cursor is visible (duh), in IG it is not. In VG, absolute motion events also work. There are 6 actions that can affect grabbing: 1. Set Fullscreen/Window (F/W). In fullscreen, a visible grab should do nothing. However, a fullscreen visible grab can be treated just like a windowed visible grab, which is what I have done to help simplify things. 2. Cursor hide/show (H/S). If the cursor is hidden when grabbing, the grab is an invisible grab. If the cursor is visible, the grab should just constrain the mouse to the window. 3. Input grab/ungrab(G/U). If grabbed, the cursor should be confined to the window as should the keyboard input. On Mac OS X, the keyboard input is implicitly grabbed by confining the cursor, except for command-tab which can switch away from the application. Should the window come to the foreground if the application is deactivated and grab input is called? This isn't necessary in this implementation because the grab state will be asserted upon activation. Using my notation, these are all the cases that need to be handled (state + action = new state). UG+U = UG UG+G = VG or IG, if cursor is visible or not UG+H = UG UG+S = UG VG+U = UG VG+G = VG VG+H = IG VG+S = VG IG+U = UG IG+G = IG IG+H = IG IG+S = VG The cases that result in the same state can be ignored in the code, which cuts it down to just 5 cases. Another issue is what happens when the app loses/gains input focus from deactivate/activate or iconify/deiconify. I think that if input focus is ever lost (outside of SDL's control), the grab state should be suspended and the cursor should become visible and active again. When regained, the cursor should reappear in its original location and/or grab state. This way, when reactivating the cursor is still in the same position as before so apps shouldn't get confused when the next motion event comes in. This is what I've done in this patch.