Ok, I'll add my two cents worth, even though this thread has been silent for quite a while:
I'm using Sonar X2 Studio (X2a build 351). The staff view snap had been working just fine with old and new projects until one day it was just gone in a project while editing midi notes. With other projects it was still working, but not with this one. No snap whatsoever and it was very hard to position midi notes after that. And I "hadn't touched anything".
After a while I almost gave it up, but then stumbled onto an old Sonar 8.5 release note (found with Google) which had a section named "3.3. Toggling Snap To Grid With the Letter N". Okay, on to Sonar staff view and press "N". Snap to grid was back! Press "N" again - snap to grid gone... Press "N" - snap is back! This was starting to look quite good.
I then went to see what function is bound to the "N" key in the staff view and found it to be "Snap Toggle Extend". The case was now solved and I haven't had to suffer since. I must have pressed "N" by accident at some point and snap to grid was gone.
So, no INI file surgery or uninstallation/reinstallation misery was required in my case, I just pressed "N".
I hope others suffering from snap-to-grid-less staff view will find this post helpful!
-Pete from Finland