Fixes for null command

App/AppDelegate.swift

@@ -105,7 +105,7 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
                     title: "Find on Page",
                     action: #selector(ShortcutResponder.findOnPage)
                 )
-                : UIKeyCommand()
+             : UIKeyCommand.null()
             ),
             
             // Refresh

App/Utilities/UIKeyCommand+ConvInit.swift

@@ -7,7 +7,15 @@
 
 import UIKit
 
+extension NSObject {
+    @objc fileprivate func _null() {}
+}
+
 extension UIKeyCommand {
+    public static func null() -> UIKeyCommand {
+        UIKeyCommand(modifiers: [], input: "", title: "", action: #selector(_null))
+    }
+    
     convenience init(modifiers: UIKeyModifierFlags, input: String, title: String, action: Selector) {
         self.init(input: input, modifierFlags: modifiers, action: action)
         self.title = title