Minor adding close png icon to avoid "doubts" in the document preview with the delete icon

main/inc/lib/document.lib.php

@@ -2553,7 +2553,7 @@ return 'application/octet-stream';
 	    	$return .= Display::url(get_lang('NewDocument'), api_get_self().'?'.api_get_cidreq().'&action=add_item&type='.TOOL_DOCUMENT.'&lp_id='.$_SESSION['oLP']->lp_id);
 	    	$return .= '</div>';
     	} else {            
-    		$return .= Display::div(Display::url(Display::return_icon('delete.png', get_lang('Close'), array(), 22), ' javascript:void(0);', array('id'=>'close_div_'.$course_info['real_id'].'_'.$session_id,'class' =>'close_div')), array('style' => 'position:absolute;right:10px'));
+    		$return .= Display::div(Display::url(Display::return_icon('close.png', get_lang('Close'), array(), 22), ' javascript:void(0);', array('id'=>'close_div_'.$course_info['real_id'].'_'.$session_id,'class' =>'close_div')), array('style' => 'position:absolute;right:10px'));
     	}
     	
     	// If you want to debug it, I advise you to do "echo" on the eval statements.