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Bug 5310

Summary: SDL_MOUSEMOTION massive random xrel & yrel values when Present(): DEVICELOST
Product: SDL Reporter: Anthony @ POW Games <ant>
Component: videoAssignee: Sam Lantinga <slouken>
Status: NEW --- QA Contact: Sam Lantinga <slouken>
Severity: normal    
Priority: P2 CC: sezeroz
Version: HG 2.0   
Hardware: x86   
OS: Windows 10   

Description Anthony @ POW Games 2020-10-08 15:47:02 UTC 
You can force a Present(): DEVICELOST in Windows by Ctrl+Alt+Del and cancelling. When the window is restored there is no harm is done, but...

If the mouse is within the window, a SDL_MOUSEMOTION event is generated with massive random xrel & yrel values. Then another SDL_MOUSEMOTION event is generated with zero xrel & yrel values. The mouse hasn't moved during this time.

Also, alt-tab away from the window and back into the window generates a SDL_MOUSEMOTION event, even though the mouse hasn't moved. But calling SDL_SetWindowFullscreen, which changes the window size and so the position of the mouse, doesn't generate a SDL_MOUSEMOTION event.

This all seems like strange behaviour. Might be related to bug 5154.

I'm not using any relative mouse mode functions. It happens in both full screen and windowed.