Show popover from CGRect of button
<p>I created a button programmatically to be added to the rightBarButtonItem.  I had to create a few buttons in the upper right with the UINavigationController, so I put them in a containerView, and then, put that as the right barButtonItem customView in the init method.  If my button and containerView are declared like this:</p>

<pre><code>UIButton *filterButton = [[UIButton alloc] initWithFrame:CGRectMake(49, 0, 44, 44)];
[filterButton setTitle:@"Filter" forState:UIControlStateNormal];
[filterButton addTarget:self action:@selector(FilterButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
UIView *containerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 248, 44)];
</code></pre>

<p>How do I get the popover to present from the filterButton rect?  My method looks like this so far, but it is not correct.</p>

<pre><code>- (IBAction)FilterButtonPressed:(id)sender {
// other code
    [self.FilterPopover presentPopoverFromRect:button.superview.bounds inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
</code></pre>
