Are you sure that the problems with the debugger are due to IntellisenseX? I see no activity of any kind in the debugger when IntellisenseX is active.
On the other hand, there are known problems if you have either PEM Editor or Document TreeView open.
By the way, there is a separate forum for Thor:
https://groups.google.com/forum/?fromgroups#!forum/FoxProThor. I encourage you to submit Thor-related questions there. You will get responses from more devs, and more rapid response as well.