Thanks for your bug report. Neither of these are bugs as far as I can tell. The maximum length is 8192 and has been for as long as I can remember. As for the speed, there is quite literally nothing that can be changed in the sendmessage routine to speed it up. The slowness is likely due to the calls to MapViewOfFile() and VirtualQuery(), both of which are related to shared memory, not to mention calls to the alias/identifier routines.
