Disappearing textures...again.

I had a disappearing texture problem ( 3D virtual Cockpit only) on my old computer, when the scenery transitioned from dusk to night, while flying a complex aircraft like the PMDG 747. By disappearing, I mean that about 1/3 of the 3D panel goes transparent. The 2D panel and the outside aircraft views are not affected. I just got a new machine (specs listed below by signature), and its still happening. I installed both HIGHMEMFIX and the UI AutomationCore fix.

Things were OK for one flight and now the problem is back. If I change the time of day back to "daytime" the textures go back to normal. This is incredibly frustrating to say the least! Are there any additional things any of you have tried that solved this problem. Thanks.