IDCMP_REQSET Intuition sends an IDCMP_REQSET message to the window each time a requester opens in that window. IDCMP_REQCLEAR Intuition sends an IDCMP_REQCLEAR message to the window each time a requester is cleared from that window. IDCMP_REQVERIFY Set this flag to allow the application to ensure it is prepared for Intuition to render a requester in the window. With this flag set, Intuition sends the application a message that a requester is pending, and then waits for the application to reply before drawing the requester in the window. If several requesters open in the window, Intuition asks the application to verify only the first one. After that, Intuition assumes that all output is being held off until all the requesters are gone. By setting the IDCMP_REQSET and IDCMP_REQCLEAR flags, the application can track how many requesters are open in the window and when the last requester is cleared. Once all of the requesters are cleared from the window, it is safe to write to the window until another IDCMP_REQVERIFY is received. See the "Verification Functions" section below for more discussion on using this flag.