Sets the delay that will occur after each mouse movement or click.
SetMouseDelay Delay , "Play"
Time in milliseconds. Use -1 for no delay at all and 0 for the smallest possible delay (however, if the Play parameter is present, both 0 and -1 produce no delay). If unset, the default delay is 10 for the traditional SendEvent mode and -1 for SendPlay mode.
The word Play applies the delay to the SendPlay mode rather than the traditional Send/SendEvent mode. If a script never uses this parameter, the delay is always -1 for SendPlay.
A short delay (sleep) is done automatically after every mouse movement or click generated by Click and MouseMove/Click/Drag (except for SendInput mode). This is done to improve the reliability of scripts because a window sometimes can't keep up with a rapid flood of mouse events.
Due to the granularity of the OS's time-keeping system, delays might be rounded up to the nearest multiple of 10 or 15. For example, a delay between 1 and 10 (inclusive) is equivalent to 10 or 15 on most Windows XP systems (and probably 2k).
A delay of 0 internally executes a Sleep(0), which yields the remainder of the script's timeslice to any other process that may need it. If there is none, Sleep(0) will not sleep at all. By contrast, a delay of -1 will never sleep.
The built-in variable A_MouseDelay contains the current setting for Send/SendEvent mode. A_MouseDelayPlay contains the current setting for SendPlay mode.
Every newly launched thread (such as a hotkey, custom menu item, or timed subroutine) starts off fresh with the default setting for this function. That default may be changed by using this function in the auto-execute section (top part of the script).
SetDefaultMouseSpeed, Click, MouseMove, MouseClick, MouseClickDrag, SendMode, SetKeyDelay, SetControlDelay, SetWinDelay
SetMouseDelay 0