SMS App Bugs

[ch1234]

I'm having a couple of problems with the messaging app:

1. When I go to compose a message and select from my contacts list, I am able to choose who to text from ALL my contacts (even Facebook contacts who's phone number I don't have). I also have some entries appearing twice for contacts that I would have stored on my SIM card as well. How can I filter this list so it only shows say my contacts synced with my GMail account for example?
2. I sometimes have MULTIPLE conversations for the same person - I'll send them an SMS and when they respond, it starts a new thread. It's annoying as it's hard to keep track of conversations this way. Is there any way I can merge threads together?
3. Similar to above but sometimes when I send an SMS to a contact, it will start a new thread itself - at one stage I had 4 conversations for the same contact.

I'm using Go SMS Pro but I still have the default app installed. I checked and this problem is happening in both of the apps. Has anybody come across these problems before?

Thanks!