This is problem unrelated to GoG. I have an Elecom Huge trackball and in some applications, the right click won't work. I've tested this on Win7 64 and Win10. The problem persists across OS. Here are some examples.

Right click works:
WoW
MM6, no mods (through GOG Galaxy)
Windows desktop (Win7 and Win64)
Panzer Corps (I and II)

Right click doesn't work:
SWTOR
MM7, no mods (through GOG Galaxy)
Windows Task Manager (Win7 and Win64)
Teamspeak
Fantasy General II
MS Visual Studio (only tested on Win7)

I've tried installing software as admin, not as admin, direct install and through another application like GOG Galaxy. If the right click works in the program it always works. Likewise for the failures, always consistent. I only use a single configuration and it is the default for the Elecom driver. And I know I would probably solve this by not using an Elecom product, but my hands shake and I need a trackball that is stable enough to damp the shaking out.

Elecom doesn't offer English language support so my options are limited to skipping over the software I can't right click inside. So my question for the community, does anyone have an idea about how to resolve this?

Thanks you.