Help !!! - (SGI Visual 320) - no prompt refresh

Help me please !
My 2 SGI Visual Ws, with under Altair HyperMesh, after node picking not refresh the video, but only after next picking, refresh the video and appear last node selection. I have already try to use the 4.0.2 version of Cobal Graphics driver.
Thi s prblem appeare with all resolutions and with all refresh frequency.

Help me, please !!!