         }
         
         required init?(coder: NSCoder) {
-            fatalError("init(coder:) has not been implemented")
-        }
-    }
-}
+            fatalError("init(coder:) invalid")
+        }
+    }
+}

            self.addSubview(button)
            
            button.frame.origin = NSMakePoint(parentTabView.buttonPadding, 3)
            button.frame.size.height = parentTabView.fontSize * 1.7
            
            let frameWidth = button.frame.width + (parentTabView.buttonPadding * 2)
            
            /// UnderLine
            underline = UnderLine()
            underline.frame.origin = NSMakePoint(selectionLineHeight, 0)
            underline.frame.size = NSMakeSize(frameWidth - (selectionLineHeight * 2), selectionLineHeight)
            self.addSubview(underline)
            
            /// Frame Size

        button.imagePosition = NSCellImagePosition.ImageLeft
        button.bordered = false
        button.enabled = false
        button.setAttributedString(tabView.fontSize, color: tabView.labelColor)
        button.sizeToFit()
        button.frame.size.height = tabView.fontSize * 1.7
        return button
    }
}

extension KSTabView.KSButton {
    private class UnderLine: NSBox {
        override init(frame frameRect: NSRect) {
            super.init(frame: frameRect)
            self.boxType = NSBoxType.Custom
            self.borderWidth = 0
            self.fillColor = NSColor.whiteColor()
