CI doesn't return the view buffer

[eluser]Unknown[/eluser]
my problem is when i load a view file , it sends it directly to the browser instead of returning it :

Code:

$output=$this->load->view('topic', $data, TRUE);

I'm using CI 2 and I haven't touched the core classes .

what is wrong ?

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Update :
I've two controllers .each controller extend another controller before it extend the CI_Controller such as :

topics_admin extends Backend(which extends CI_controller)
topics extends Frontend (which extends CI_controller)

the first controller behaves as expected but the second one has the problem i've explained
there is no major difference between the 2 Frontend & Backend controllers .

[eluser]Unknown[/eluser]
I've found it .
There was undefined function in the view
and it didn't show the error message because the function was in a tag attribute like that :

Code:

<a href="&lt;?=member_url()?&gt;/topics">Title</a>

[eluser]Unknown[/eluser]
Good work