Smile Go sms Pro Group contacts

Asalam-o-Alikum To all Of you here...!!
I have a strange problem with my Go sms Pro. I love texting friends, so i manage there accounts in groups, i.e. Friends. I added there numbers there, but whenever i go to write msg and click on the group, then the contacts hide,
Example, i have 10 contacts in a group, but when i sen text from go sms pro, it shows only 4 or 5 contacts. The others hides
But that problems is only with Go sms pro.
Any body can help an solve my problem please?
I love to use go sms Pro because its easy and most customizable app.
I reset my phone as well, and reinstalled the app etc.
But still got the same problem