For some reason I have not been able to get the accelerated opengl to work…but at the moment I have not had time to look into it too far - so it could well be something I am doing wrong, or something about my particular setup (dual monitor perhaps)? But I will look into more over the next weekend.
I uninstalled the old version of vcxsrv that I had installed from a release a while back (I mostly run the compiled-from-source version out of the project directory) and I ran into a problem with my laptop. I suddenly started to get the dreaded 'This application has failed to start because the application configuration is incorrect. Reinstalling the application may fix this problem." message. Reinstalling every version of the C runtime that I could get my hands on did not help, but I was able to fix the problem by copying the c:\windows\winsxs folder from a similar system to mine (dangerous I know). Now this might NOT have been because of your software. I have been fighting a battle with several source control systems (TortoiseSVN/HG and Git) and it could be because of uninstalling and reinstalling them several times. I wish you would look into it though. Since you are dealing with the basic C runtime would it make more sense to just leave them (not uninstall them)?
I have noticed to that running the uninstall sometimes is uninstalling the c-run time from the winsxs directory. When other applications are using these dlls, this may give problems. I thought the install system was keeping track on how many applications had installed the run-time, but it looks like this is not the case. The easiest solution is indeed to not uninstall the c-runtime. I will update the nsis file.