Actually implemented it

PixiEditor/Helpers/Extensions/ToolbarHelpers.cs

@@ -1,10 +1,6 @@
-using PixiEditor.Models.Tools.ToolSettings.Settings;
+using System;
+using PixiEditor.Models.Tools.ToolSettings.Settings;
 using PixiEditor.Models.Tools.ToolSettings.Toolbars;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace PixiEditor.Helpers.Extensions
 {

PixiEditor/Models/Tools/ToolSettings/Toolbars/SelectToolToolbar.cs

@@ -1,4 +1,5 @@
-using PixiEditor.Models.Tools.ToolSettings.Settings;
+using PixiEditor.Models.Enums;
+using PixiEditor.Models.Tools.ToolSettings.Settings;
 
 namespace PixiEditor.Models.Tools.ToolSettings.Toolbars
 {
@@ -6,7 +7,7 @@ namespace PixiEditor.Models.Tools.ToolSettings.Toolbars
     {
         public SelectToolToolbar()
         {
-            Settings.Add(new DropdownSetting("SelectMode", new[] { "New", "Add", "Subtract" }, "Selection type"));
+            Settings.Add(new EnumSetting<SelectionType>("SelectMode", "Selection type"));
         }
     }
 }