UI - Fix possible exception when showing dialogs

Profile editor - Limit undo/redo to 20 actions for now
Plugins - Fix custom icons not displaying in settings windows

src/Artemis.Core/Models/Profile/Profile.cs

@@ -25,8 +25,8 @@ namespace Artemis.Core
             Scripts = new List<ProfileScript>();
             ScriptConfigurations = new List<ScriptConfiguration>();
 
-            UndoStack = new Stack<string>();
-            RedoStack = new Stack<string>();
+            UndoStack = new MaxStack<string>(20);
+            RedoStack = new MaxStack<string>(20);
 
             Load();
         }
@@ -75,8 +75,8 @@ namespace Artemis.Core
         /// </summary>
         public ProfileEntity ProfileEntity { get; internal set; }
 
-        internal Stack<string> UndoStack { get; set; }
-        internal Stack<string> RedoStack { get; set; }
+        internal MaxStack<string> UndoStack { get; set; }
+        internal MaxStack<string> RedoStack { get; set; }
 
         /// <inheritdoc />
         public override void Update(double deltaTime)

src/Artemis.Core/Services/Storage/ProfileService.cs

@@ -470,7 +470,7 @@ namespace Artemis.Core.Services
             // Keep the profile from being rendered by locking it
             lock (profile)
             {
-                if (!profile.UndoStack.Any())
+                if (profile.UndoStack.Count == 0)
                 {
                     _logger.Debug("Undo profile update - Failed, undo stack empty");
                     return false;
@@ -496,7 +496,7 @@ namespace Artemis.Core.Services
             // Keep the profile from being rendered by locking it
             lock (profile)
             {
-                if (!profile.RedoStack.Any())
+                if (profile.RedoStack.Count == 0)
                 {
                     _logger.Debug("Redo profile update - Failed, redo empty");
                     return false;

src/Artemis.Core/Utilities/MaxStack.cs

@@ -0,0 +1,118 @@
+// Source: https://ntsblog.homedev.com.au/index.php/2010/05/06/c-stack-with-maximum-limit/
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace Artemis.Core
+{
+    /// <summary>
+    /// Generic stack implementation with a maximum limit
+    /// When something is pushed on the last item is removed from the list
+    /// </summary>
+    [Serializable]
+    internal class MaxStack<T>
+    {
+        #region Fields
+
+        private int _limit;
+        private LinkedList<T> _list;
+
+        #endregion
+
+        #region Constructors
+
+        public MaxStack(int maxSize)
+        {
+            _limit = maxSize;
+            _list = new LinkedList<T>();
+
+        }
+
+        #endregion
+
+        #region Public Stack Implementation
+
+        public void Push(T value)
+        {
+            if (_list.Count == _limit)
+            {
+                _list.RemoveLast();
+            }
+            _list.AddFirst(value);
+        }
+
+        public T Pop()
+        {
+            if (_list.Count > 0)
+            {
+                T value = _list.First.Value;
+                _list.RemoveFirst();
+                return value;
+            }
+            else
+            {
+                throw new InvalidOperationException("The Stack is empty");
+            }
+
+
+        }
+
+        public T Peek()
+        {
+            if (_list.Count > 0)
+            {
+                T value = _list.First.Value;
+                return value;
+            }
+            else
+            {
+                throw new InvalidOperationException("The Stack is empty");
+            }
+
+        }
+
+        public void Clear()
+        {
+            _list.Clear();
+
+        }
+
+        public int Count
+        {
+            get { return _list.Count; }
+        }
+
+        /// <summary>
+        /// Checks if the top object on the stack matches the value passed in
+        /// </summary>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public bool IsTop(T value)
+        {
+            bool result = false;
+            if (this.Count > 0)
+            {
+                result = Peek().Equals(value);
+            }
+            return result;
+        }
+
+        public bool Contains(T value)
+        {
+            bool result = false;
+            if (this.Count > 0)
+            {
+                result = _list.Contains(value);
+            }
+            return result;
+        }
+
+        public IEnumerator GetEnumerator()
+        {
+            return _list.GetEnumerator();
+        }
+
+        #endregion
+
+    }
+}