vim : Yanking doesn't work between file
<p>I'm stuck up with a weird problem. I am trying to copy(yy) and paste(p) a line from one file to another (in  split screen). It doesn't look it its working. However, yy, p works in the same file and with another file opened in another "tab". Would be really helpful if someone could tell me how to fix this. Spending a lot of time fixing this :(.</p>

<p>Thanks,
Omkar</p>