ide/designer/findCtx: Fixed memory corruption
- A static global variable was not being reset to null as it should and is a potential candidate for the cause of random IDE crashes
- A bad class ended up being set with 'SetThisClass'
- This could be reproduced systematically under MemoryGuard by first auto-completing an OnCompare method with a '(' inside a class,
  and then attempting to auto-complete an OnCompare method inside a struct (which does not yet work), e.g. Object3DSFormat.ec