Finally I have found reason why my custom polygon handlers Show Weights and Show Edge Weights were not showing properly weights in viewports in LightWave v9.6 (it worked well in previous versions, since v8.3).
If you're owner of TrueArt's Modeling Pack http://modelingpack.trueart.eu and/or bought ShowWeights alone please write to me with order id, shopping system that you have used Plimus/Reg.Net, and system information.txt, and I will send you free update that should work in LightWave v9.6 in Legacy GL mode (LW new GL mode doesn't have text() function at least in build 1539, I don't know whether NewTek fixed it in newer builds).
For those who don't know ShowWeights and/or ShowEdgeWeights, it's tool for displaying weights of mapped points/edges (edge sharpness of Catmull-Clark Sub-D Type) in viewport, while you edit vmaps using any either build-in LW or 3rd party tool (parallel in multi-threading). It's especially useful for game makers who often make characters with weight only bones.
You can find more informations on our website http://www.trueart.eu