I just reported this on GitHub, I’m not sure if the correct ettiquite is to cross post to Cesium Forums. Feel free to delete if this is not appropriate.
Otherwise I just wanted to point out a weird bug. I followed along with the Draw on Globe SandCastle demo. In this demo you can click on the globe and move your cursor and a path appears underneath.
When I ported this to my application I got really strange path positions that were far away from where I clicked.
After hours I finally chased it down to disabling the baseLayerPicker on the Viewer. Since I’m using my own TMS I don’t need a base layer picker. However it seems to break viewer.scene.pickPosition.
See this sand castle demo. Try tilting the screen and watch the paths be far off. Then re-enable baseLayerPicker and it works again.