     
     // MARK: View Methods
     
-    /// add left padding for popup button
+    /// add paddings
     override var frame: NSRect {
         didSet {
-            guard frame.minX < self.leftPadding else { return }  // avoid infinity loop
+            guard frame.minX < self.leadingPadding else { return }  // avoid infinity loop
             
-            frame.origin.x += self.leftPadding
-            frame.size.width -= self.leftPadding
+            frame.origin.x += self.leadingPadding
+            frame.size.width -= self.leadingPadding
+            frame.size.width -= self.tailingPadding
         }
     }
     

        
        super.init(coder: coder)
        
        // make sure frame to be initialized (Otherwise input area can be arranged in a wrong place.)
        let frame = self.frame
        self.frame = frame
    }

    
    // MARK: Private Properties
    
    private let leadingPadding: CGFloat = 28.0  // for history button
    private let tailingPadding: CGFloat = 22.0  // for clear buttton
    
    
    
