Should not recreate pbuffers current to another thread

[amonakov]

Refcounting pbuffers to detect the problem is too conservative since we can't decrement the counter if a thread simply exits.

Using windows instead of pbuffers is problematic since GL is allowed to not render anything at all due to pixel ownership test, but apparently works on nVidia.

[ArchangeGabriel]

I’m planning to release a new version for Ubuntu. Do you have an ETA for solving this issue, or should I go with what is already published?

[amonakov]

Please go ahead.