diff --git a/.swift-version b/.swift-version
index 9f55b2c..5186d07 100644
--- a/.swift-version
+++ b/.swift-version
@@ -1 +1 @@
-3.0
+4.0
diff --git a/NibDesignable.podspec b/NibDesignable.podspec
index 384d5ff..986cd58 100644
--- a/NibDesignable.podspec
+++ b/NibDesignable.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name = 'NibDesignable'
-  s.version = '3.0.0'
+  s.version = '4.0.0'
   s.license = { :type => 'MIT', :file => 'LICENSE' }
   s.summary = 'Elegant way of enabling IBDesignable on your nib-based views'
   s.homepage = 'https://github.com/mbogh/NibDesignable'
diff --git a/NibDesignable.swift b/NibDesignable.swift
index 756e617..a537861 100644
--- a/NibDesignable.swift
+++ b/NibDesignable.swift
@@ -27,21 +27,21 @@ public protocol NibDesignableProtocol: NSObjectProtocol {
     /**
      Identifies the view that will be the superview of the contents loaded from
      the Nib. Referenced in setupNib().
-
+     
      - returns: Superview for Nib contents.
      */
     var nibContainerView: UIView { get }
     // MARK: - Nib loading
-
+    
     /**
      Called to load the nib in setupNib().
-
+     
      - returns: UIView instance loaded from a nib file.
      */
     func loadNib() -> UIView
     /**
      Called in the default implementation of loadNib(). Default is class name.
-
+     
      - returns: Name of a single view nib file.
      */
     func nibName() -> String
@@ -49,10 +49,10 @@ public protocol NibDesignableProtocol: NSObjectProtocol {
 
 extension NibDesignableProtocol {
     // MARK: - Nib loading
-
+    
     /**
      Called to load the nib in setupNib().
-
+     
      - returns: UIView instance loaded from a nib file.
      */
     public func loadNib() -> UIView {
@@ -60,9 +60,9 @@ extension NibDesignableProtocol {
         let nib = UINib(nibName: self.nibName(), bundle: bundle)
         return nib.instantiate(withOwner: self, options: nil)[0] as! UIView // swiftlint:disable:this force_cast
     }
-
+    
     // MARK: - Nib loading
-
+    
     /**
      Called in init(frame:) and init(aDecoder:) to load the nib and add it as a subview.
      */
@@ -77,12 +77,9 @@ extension NibDesignableProtocol {
 }
 
 extension UIView {
-    public var nibContainerView: UIView {
-        return self
-    }
     /**
      Called in the default implementation of loadNib(). Default is class name.
-
+     
      - returns: Name of a single view nib file.
      */
     open func nibName() -> String {
@@ -92,13 +89,16 @@ extension UIView {
 
 @IBDesignable
 open class NibDesignable: UIView, NibDesignableProtocol {
+    public var nibContainerView: UIView {
+        return self
+    }
 
     // MARK: - Initializer
     override public init(frame: CGRect) {
         super.init(frame: frame)
         self.setupNib()
     }
-
+    
     // MARK: - NSCoding
     required public init?(coder aDecoder: NSCoder) {
         super.init(coder: aDecoder)
@@ -108,16 +108,16 @@ open class NibDesignable: UIView, NibDesignableProtocol {
 
 @IBDesignable
 open class NibDesignableTableViewCell: UITableViewCell, NibDesignableProtocol {
-    public override var nibContainerView: UIView {
+    public var nibContainerView: UIView {
         return self.contentView
     }
-
+    
     // MARK: - Initializer
     override public init(style: UITableViewCellStyle, reuseIdentifier: String?) {
         super.init(style: style, reuseIdentifier: reuseIdentifier)
         self.setupNib()
     }
-
+    
     // MARK: - NSCoding
     required public init?(coder aDecoder: NSCoder) {
         super.init(coder: aDecoder)
@@ -127,33 +127,36 @@ open class NibDesignableTableViewCell: UITableViewCell, NibDesignableProtocol {
 
 @IBDesignable
 open class NibDesignableTableViewHeaderFooterView: UITableViewHeaderFooterView, NibDesignableProtocol {
-
-	public override var nibContainerView: UIView {
-			return self.contentView
-	}
-
-	// MARK: - Initializer
-	override public init(reuseIdentifier: String?) {
-		super.init(reuseIdentifier: reuseIdentifier)
-		self.setupNib()
-	}
-
-	// MARK: - NSCoding
-	required public init?(coder aDecoder: NSCoder) {
-		super.init(coder: aDecoder)
-		self.setupNib()
-	}
+    
+    public var nibContainerView: UIView {
+        return self.contentView
+    }
+    
+    // MARK: - Initializer
+    override public init(reuseIdentifier: String?) {
+        super.init(reuseIdentifier: reuseIdentifier)
+        self.setupNib()
+    }
+    
+    // MARK: - NSCoding
+    required public init?(coder aDecoder: NSCoder) {
+        super.init(coder: aDecoder)
+        self.setupNib()
+    }
 }
 
 @IBDesignable
 open class NibDesignableControl: UIControl, NibDesignableProtocol {
+    public var nibContainerView: UIView {
+        return self
+    }
 
     // MARK: - Initializer
     override public init(frame: CGRect) {
         super.init(frame: frame)
         self.setupNib()
     }
-
+    
     // MARK: - NSCoding
     required public init?(coder aDecoder: NSCoder) {
         super.init(coder: aDecoder)
@@ -163,13 +166,16 @@ open class NibDesignableControl: UIControl, NibDesignableProtocol {
 
 @IBDesignable
 open class NibDesignableCollectionReusableView: UICollectionReusableView, NibDesignableProtocol {
+    public var nibContainerView: UIView {
+        return self
+    }
 
     // MARK: - Initializer
     override public init(frame: CGRect) {
         super.init(frame: frame)
         self.setupNib()
     }
-
+    
     // MARK: - NSCoding
     required public init?(coder aDecoder: NSCoder) {
         super.init(coder: aDecoder)
@@ -179,19 +185,20 @@ open class NibDesignableCollectionReusableView: UICollectionReusableView, NibDes
 
 @IBDesignable
 open class NibDesignableCollectionViewCell: UICollectionViewCell, NibDesignableProtocol {
-    public override var nibContainerView: UIView {
+    public var nibContainerView: UIView {
         return self.contentView
     }
-
+    
     // MARK: - Initializer
     override public init(frame: CGRect) {
         super.init(frame: frame)
         self.setupNib()
     }
-
+    
     // MARK: - NSCoding
     required public init?(coder aDecoder: NSCoder) {
         super.init(coder: aDecoder)
         self.setupNib()
     }
 }
+