Visualizer no longer working in gSender 1.6?

Visualizer was working fine on gSender 1.5.4 on my old Thinkpad T500 laptop, but no longer works in 1.6 or 1.6.1. I get a blank screen, only the “light” mode displays something, but when I try the full visualizer the entire screen goes blank and I have to exit gSender and restart. Anyone knows if they have switched to a more recent version of webGL - which might explain why it’s not working on my old laptop ? tia