Android : Android: Facebook login dialog does not show soft keyboard

I am using Facebook SDK v3.17.1 and use LoginButton for basic authentication.

I tested it in my Nexus 5 and it is working properly, after pressing the login button the prompt appears that requires confirmation for the permission.

However, when I run it on my Nexus 7, I was required to login first even though I already have a native FB app (in Nexus 5, there is no login), so I tried to enter my login details. But I can't enter any text because the soft keyboard is not showing even if I tap on the input field.

Is this a device problem or there is something wrong with Facebook SDK? I tried it on Galaxy Note and the issue also occurs. In Galaxy S3, the issue is not occuring. I'm a bit confused on what is happening.

Thanks for any help.

Link for the Nexus 7 screenshot http://i.stack.imgur.com/FIKJl.png