When the mouse is set to left-handed, the mouse pointer is not affected visually by the setting so it continues to point the same direction (slightly to the left). I think that the mouse pointer should be reversed so that it points slightly to the right when the mouse is set to left-handed. The ideal solution would be to automatically flip the relevant mouse pointers horizontally on-the-fly so that regardless of the pointer theme they are reversed when the mouse orientation is set to left-handed. However, some pointers in a theme would need to remain unaffected (like left/right window resize) which complicates the implementation of this solution. Another solution would be to ship two pointer themes: The default theme plus a slightly modified, left-handed variation of the default theme in which the affected pointers have been flipped horizontally.
The server is not really aware of the left/right distinction, it sees it just as some swapping between the order of the buttons. So doing it automatically sounds impossible (in addition to the problems you mentioned already). So the only way would be to provide additional pointer sets, and add support to the application which swap the buttons to also change the pointer set used.
Mass closure: This bug has been untouched for more than six years, and is not obviously still valid. Please file a new report if you continue to experience issues with a current server.
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