Hi, In dlls/user32/tests/msg.c, there's the following enum: typedef enum { sent=0x1, posted=0x2, parent=0x4, wparam=0x8, lparam=0x10, defwinproc=0x20, beginpaint=0x40, optional=0x80, hook=0x100, winevent_hook=0x200 } msg_flags_t; Can someone explain what these flags mean? parent defwinproc beginpaint hook winevent_hook - Lei