Here are all the details: I had X2 working "fine" - by that, I mean with the known bugs that were pending the X2a fix - with certainly no
fundamental issue like this mouse issue. I downloaded the update, ran it, and discovered this issue suddenly. No new hardware OR software other than the Sonar X2a has been added. Further, I checked it on a brand new project i.e. with no tracks, no plugins, in a word: clean. The issue persists. My system, as you can see is not old and considering all pretenses here, it must be a compatibility that CW did not thoroughly check over testing X2a.
And just to be thorough, my system:
Gigabyte EX58-UD4P Intel X58.
12Gb of Kingston HyperX DDR3/1600 Mhz Triple Ch. RAM.
Intel i7 920 2.66GHz LGA1366
Win 7 64 SP1 with the latest BIOS
Sonar 64
Standard PS2 mouse/keyboard