Class which installs a global event filter, and listens for move events which may affect the absolute position of widgets registered with the monitor for Linux.First un-register the target, in case this is being called as a result of re-parenting. This is not the most efficient way to update the target hash, but since this is not likely to be a frequent operation, simplicity is preferred over outright speed. In any case, re-parenting of the video widget leads to re-creation of native windows, which is likely to take far more processing than any implementation of this // function for Linux.

-Class which installs a global event filter, and listens for move events which may affect the absolute position of widgets registered with the monitor for Linux.First un-register the target, in case this is being called as a result　of re-parenting. This is not the most efficient way to update the target hash, but since this is not likely to be a frequent operation, simplicity is preferred over outright speed. In any case, re-parenting of the video widget leads to re-creation of native windows, which is likely to take far more processing than any implementation of this // function for Linux.