In my case, since I have 8 CPU threads / cores, unless the flash plugin is multi-threaded, I do not see how it can prevent x2go from getting the resources it needs. The flash plugin certainly does not appear to peg all 8 CPU threads at 100%. So it seems to me there should be enough resources left for x2go. There is plenty of spare CPU capacity for Xorg when I run the flash plugin natively. But it looked like x2go and the flash plugin were competing for resources from the same CPU thread. Hmmm.