IntControl (43, p1, 0, 0, 0)
Enable/disable "WaitForInputIdle".
p1 Meaning
0 Don't wait for application to be ready.
1 Wait for application to be ready (default).
-1 Don't change (just return current setting)
This controls whether SendKey, SendKeysTo and SendKeysChild attempts to wait until the active application is ready to accept input before sending each keystroke. Returns the previous setting.