diff --git a/src/EditableNSTextField.swift b/src/EditableNSTextField.swift
index 0a5c172..07d14d6 100644
--- a/src/EditableNSTextField.swift
+++ b/src/EditableNSTextField.swift
@@ -11,6 +11,7 @@ final class EditableNSTextField: NSTextField {
                 NSEvent.ModifierFlags.deviceIndependentFlagsMask.rawValue)
                 == commandKey 
             {
+                // TODO: Use virtual key codes instead of characters.
                 switch event.charactersIgnoringModifiers! {
                 case "x":
                     if NSApp.sendAction(#selector(NSText.cut(_:)),
diff --git a/src/Helpers.swift b/src/Helpers.swift
index 2f4ad7a..3bda404 100644
--- a/src/Helpers.swift
+++ b/src/Helpers.swift
@@ -7,6 +7,20 @@ fileprivate let logger = Logger(
     category: String("Helpers")
 )
 
+let OSCtrl  = NSEvent.ModifierFlags.control.rawValue
+let OSCmd   = NSEvent.ModifierFlags.command.rawValue
+let OSOpt   = NSEvent.ModifierFlags.option.rawValue
+let OSShift = NSEvent.ModifierFlags.shift.rawValue
+let OSMods  = UInt(OSCtrl | OSCmd | OSOpt | OSShift)
+
+func modsContains(keys: UInt, in modifiers: UInt) -> Bool {
+    return (modifiers & keys) == keys && ((modifiers ^ keys) & OSMods) == 0
+}
+
+func modsContainsNone(in modifiers: UInt) -> Bool {
+    return (modifiers & OSMods) == 0
+}
+
 enum ViewConstants {
     static let spacing2: CGFloat = 2
     static let spacing5: CGFloat = 2
diff --git a/src/PopoverPanel.swift b/src/PopoverPanel.swift
index b025adb..f5e403d 100644
--- a/src/PopoverPanel.swift
+++ b/src/PopoverPanel.swift
@@ -1,4 +1,5 @@
 import Cocoa
+import Carbon
 import OSLog
 
 class PopoverPanel: NSPanel {
@@ -41,32 +42,27 @@ class PopoverPanel: NSPanel {
 
     override func performKeyEquivalent(with event: NSEvent) -> Bool {
         let modifiers = event.modifierFlags.rawValue
-        let command = NSEvent.ModifierFlags.command.rawValue
-        let shift = NSEvent.ModifierFlags.shift.rawValue
-        let control = NSEvent.ModifierFlags.control.rawValue
-        let option = NSEvent.ModifierFlags.option.rawValue
+        let key = event.keyCode
 
         if event.type == NSEvent.EventType.keyDown {
-            // Checks if flags contains a command key,
-            // then check if flags doesn't contain any other keys.
-            if (modifiers & command) == command,
-                (modifiers & (control | shift | option)) == 0,
-                event.keyCode == 12 // Q
+            if modsContains(keys: OSCmd, in: modifiers) &&
+                key == kVK_ANSI_Q
             {
                 NSApplication.shared.terminate(self)
                 return true
-            } else if (modifiers & command) == command,
-                (modifiers & (control | shift | option)) == 0,
-                event.keyCode == 13 // W
+            } else if modsContains(keys: OSCmd, in: modifiers) &&
+                key == kVK_ANSI_W
             {
                 resignKey()
                 return true
-            } else if (modifiers & (command & shift)) == command & shift,
-                (modifiers & (control | option)) == 0,
-                event.keyCode == 15 // R
+                
+            } else if modsContains(keys: OSCmd | OSShift,
+                in: modifiers) &&
+                key == kVK_ANSI_R
             {
                 PathManager.shared.rebuildIndex()
-            } else if event.keyCode == 53 { // ESC
+                return true
+            } else if key == kVK_Escape {
                 resignKey()
                 return true
             }
diff --git a/src/SearchViewController.swift b/src/SearchViewController.swift
index b4c3c3e..df1008d 100644
--- a/src/SearchViewController.swift
+++ b/src/SearchViewController.swift
@@ -1,4 +1,5 @@
 import AppKit
+import Carbon
 import OSLog
 
 class SearchViewController: NSViewController, NSTextFieldDelegate,
@@ -151,25 +152,20 @@ class SearchViewController: NSViewController, NSTextFieldDelegate,
         { [weak self] event in
             let key = event.keyCode
             let modifiers = event.modifierFlags.rawValue
-            let command = NSEvent.ModifierFlags.command.rawValue
-            let shift = NSEvent.ModifierFlags.shift.rawValue
-            let control = NSEvent.ModifierFlags.control.rawValue
-            let option = NSEvent.ModifierFlags.option.rawValue
 
             // TODO: Implement helper functions for modifiers.
             if let controller = self {
-                if ((modifiers & control) == control &&
-                    (modifiers & (command | shift | option)) == 0 &&
-                    key == 35) || // P
-                    (modifiers & (command | control | shift | option)) == 0 &&
-                    (key == 126) // UP
+                if modsContains(keys: OSCtrl, in: modifiers) &&
+                        key == kVK_ANSI_P ||
+                    modsContainsNone(in: modifiers) &&
+                        key == kVK_UpArrow
                 {
                     controller.programsTableViewSelection -= 1
-                } else if ((modifiers & control) == control &&
-                    (modifiers & (command | shift | option)) == 0 &&
-                    key == 45) || // N
-                    (modifiers & (command | control | shift | option)) == 0 &&
-                    (key == 125) // DOWN
+                    
+                } else if modsContains(keys: OSCtrl, in: modifiers) &&
+                        key == kVK_ANSI_N ||
+                    modsContainsNone(in: modifiers) &&
+                        (key == kVK_DownArrow)
                 {
                     controller.programsTableViewSelection += 1
                 }
@@ -322,10 +318,12 @@ class SearchViewController: NSViewController, NSTextFieldDelegate,
         doCommandBy commandSelector: Selector) -> Bool
     {
         if commandSelector == #selector(NSResponder.insertNewline(_:)) {
-            let program = programsList[programsTableViewSelection]
-            openProgram(program)
-            NSApp.sendAction(#selector(NSResponder.selectAll(_:)),
-                to: nil, from: self)
+            if programsList.count > 0 {
+                let program = programsList[programsTableViewSelection]
+                openProgram(program)
+                NSApp.sendAction(#selector(NSResponder.selectAll(_:)),
+                    to: nil, from: self)
+            }
             return true
         } else if commandSelector == #selector(NSResponder.insertTab(_:)) {
             return true