      - Returns: The bottom NSLayoutConstraint if found.
      */
     public var bottomConstraint: NSLayoutConstraint? {
-        return constraintForView(self, attribute: .bottom)
+        return constraintForView(self, attribute: .bottom, existsOnView: self.superview)
     }
     
     /** Gets the height constraint if found.

    - Returns: The right NSLayoutConstraint if found.
     */
    public var rightConstraint: NSLayoutConstraint? {
        return constraintForView(self, attribute: .right)
    }
        
    /** Gets the top constraint if found.

    - Returns: The height NSLayoutConstraint if found.
    */
    public var heightConstraint: NSLayoutConstraint? {
        return constraintForView(self, attribute: .height, existsOnView: self)
    }
    
    /** Gets the width constraint if found.
