UnderminersTeam · Genouka · May 19, 2026 · May 19, 2026 · May 19, 2026 · May 28, 2026
diff --git a/.gitignore b/.gitignore
@@ -333,3 +333,4 @@ Test/Test - Backup.csproj
 UndertaleModLib/UndertaleModLib - Backup.csproj
 UndertaleModTests/UndertaleModTests - Backup.csproj
 UndertaleModLib/gitversion.txt
+/UndertaleModTool/Localization/Strings.Designer.cs
diff --git a/UndertaleModTool/Controls/AudioFileReference.xaml b/UndertaleModTool/Controls/AudioFileReference.xaml
@@ -1,14 +1,15 @@
-<UserControl x:Class="UndertaleModTool.AudioFileReference"
+<UserControl x:Class="UndertaleModTool.AudioFileReference"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
-             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
              xmlns:local="clr-namespace:UndertaleModTool"
-             mc:Ignorable="d" 
+             xmlns:loc="clr-namespace:UndertaleModTool.Localization"
+             mc:Ignorable="d"
              d:DesignHeight="20" d:DesignWidth="300">
     <UserControl.Resources>
         <local:ContextMenuDark x:Key="contextMenu">
-            <local:MenuItemDark Header="Open in new tab" Click="OpenInNewTabItem_Click"/>
+            <local:MenuItemDark Header="{loc:Loc Common_OpenInNewTab}" Click="OpenInNewTabItem_Click"/>
         </local:ContextMenuDark>
     </UserControl.Resources>
     <Grid>
@@ -32,7 +33,7 @@
             </TextBox.Style>
         </local:TextBoxDark>
         <local:TextBoxDark Grid.Column="1" x:Name="ObjectText" IsReadOnly="True" Cursor="Arrow" AllowDrop="True"
-                           ToolTip="This is an object reference. Drag and drop an object of matching type from the tree on the left to change it!"
+                           ToolTip="{loc:Loc Ctrl_ObjRefToolTip}"
                            ToolTipService.InitialShowDelay="250"
                            PreviewDragOver="TextBox_DragOver" PreviewDrop="TextBox_Drop" PreviewMouseDoubleClick="TextBox_MouseDoubleClick" PreviewMouseDown="Details_MouseDown">
             <TextBox.Style>
@@ -60,14 +61,14 @@
                         </DataTrigger>
                         <DataTrigger Binding="{Binding AudioID, RelativeSource={RelativeSource AncestorType=UserControl}}" Value="-1">
                             <DataTrigger.Setters>
-                                <Setter Property="Text" Value="(null)"/>
+                                <Setter Property="Text" Value="{loc:Loc Common_Null}"/>
                             </DataTrigger.Setters>
                         </DataTrigger>
                     </Style.Triggers>
                 </Style>
             </TextBox.Style>
         </local:TextBoxDark>
-        <local:ButtonDark Grid.Column="2" Click="Details_Click" MouseDown="Details_MouseDown" Content=" ... " ToolTip="Open referenced object">
+        <local:ButtonDark Grid.Column="2" Click="Details_Click" MouseDown="Details_MouseDown" Content=" ... " ToolTip="{loc:Loc Ctrl_OpenReferencedObject}">
             <Button.Style>
                 <Style TargetType="{x:Type Button}">
                     <Style.Triggers>
@@ -78,7 +79,7 @@
                 </Style>
             </Button.Style>
         </local:ButtonDark>
-        <local:ButtonDark Grid.Column="3" Click="Remove_Click" Content=" X " ToolTip="Remove reference">
+        <local:ButtonDark Grid.Column="3" Click="Remove_Click" Content=" X " ToolTip="{loc:Loc Ctrl_RemoveReference}">
             <Button.Style>
                 <Style TargetType="{x:Type Button}">
                     <Style.Triggers>
@@ -92,4 +93,4 @@
             </Button.Style>
         </local:ButtonDark>
     </Grid>
-</UserControl>
+</UserControl>
diff --git a/UndertaleModTool/Controls/ColorPicker.xaml.cs b/UndertaleModTool/Controls/ColorPicker.xaml.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Globalization;
@@ -14,6 +14,7 @@
 using System.Windows.Media.Imaging;
 using System.Windows.Navigation;
 using System.Windows.Shapes;
+using UndertaleModTool.Localization;
 
 namespace UndertaleModTool
 {
@@ -59,7 +60,7 @@ public ColorPicker()
             ColorText.SetBinding(TextBox.TextProperty, binding);
 
             ColorText.MaxLength = HasAlpha ? 9 : 7;
-            ColorText.ToolTip = $"#{(HasAlpha ? "AA" : "")}BBGGRR";
+            ColorText.ToolTip = string.Format(LocalizationSource.GetString("Msg_ColorFormatHint"), HasAlpha ? "AA" : "");
             ToolTipService.SetInitialShowDelay(ColorText, 250);
         }
 
@@ -78,7 +79,7 @@ private static void OnHasAlphaChanged(DependencyObject dependencyObject, Depende
             colorPicker.ColorText.SetBinding(TextBox.TextProperty, binding);
 
             colorPicker.ColorText.MaxLength = hasAlpha ? 9 : 7;
-            colorPicker.ColorText.ToolTip = $"#{(hasAlpha ? "AA" : "")}BBGGRR";
+            colorPicker.ColorText.ToolTip = string.Format(LocalizationSource.GetString("Msg_ColorFormatHint"), hasAlpha ? "AA" : "");
         }
     }
 
@@ -123,11 +124,11 @@ public object ConvertBack(object value, Type targetType, object parameter, Cultu
                 bool hasAlpha = bool.Parse((string)parameter);
 
                 if (val[0] != '#')
-                    return new ValidationResult(false, "Invalid color string");
+                    return new ValidationResult(false, LocalizationSource.GetString("Msg_InvalidColorString"));
 
                 val = val[1..];
                 if (val.Length != (hasAlpha ? 8 : 6))
-                    return new ValidationResult(false, "Invalid color string");
+                    return new ValidationResult(false, LocalizationSource.GetString("Msg_InvalidColorString"));
 
                 if (!hasAlpha)
                     val = "FF" + val; // add alpha (255)

diff --git a/UndertaleModTool/Controls/FlagsBox.xaml b/UndertaleModTool/Controls/FlagsBox.xaml
@@ -1,9 +1,10 @@
-<UserControl x:Class="UndertaleModTool.FlagsBox"
+<UserControl x:Class="UndertaleModTool.FlagsBox"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
              xmlns:local="clr-namespace:UndertaleModTool"
+             xmlns:loc="clr-namespace:UndertaleModTool.Localization"
              mc:Ignorable="d"
              d:DesignHeight="450" d:DesignWidth="800"
              x:Name="flagsBox">
@@ -12,7 +13,7 @@
     </UserControl.Resources>
     <StackPanel>
         <TextBox Text="{Binding Value, ElementName=flagsBox}" />
-        <Expander Header="Flags">
+        <Expander Header="{loc:Loc Common_Flags}">
             <ItemsControl ItemsSource="{Binding Value, ElementName=flagsBox, Converter={StaticResource enumToValuesConverter}}">
                 <ItemsControl.ItemTemplate>
                     <DataTemplate>
@@ -35,4 +36,4 @@
             </ItemsControl>
         </Expander>
     </StackPanel>
-</UserControl>
+</UserControl>
diff --git a/UndertaleModTool/Controls/ResourceListTreeViewItem.xaml b/UndertaleModTool/Controls/ResourceListTreeViewItem.xaml
@@ -1,31 +1,29 @@
 <TreeViewItem x:Class="UndertaleModTool.ResourceListTreeViewItem"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
-             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
              xmlns:local="clr-namespace:UndertaleModTool"
              xmlns:undertalelib="clr-namespace:UndertaleModLib;assembly=UndertaleModLib"
+             xmlns:loc="clr-namespace:UndertaleModTool.Localization"
              mc:Ignorable="d">
 
     <TreeViewItem.Resources>
         <DataTemplate x:Key="DefaultNullItemTemplate">
-            <TextBlock Text="(null)"/>
+            <TextBlock Text="{loc:Loc Common_Null}"/>
         </DataTemplate>
 
         <local:ImplementsInterfaceConverter x:Key="ImplementsInterfaceConverter"/>
 
         <local:ContextMenuDark x:Key="UndertaleResourceMenu" Opened="MenuItem_ContextMenuOpened">
-            <MenuItem Header="Open in new tab" Click="MenuItem_OpenInNewTab_Click"/>
-            <MenuItem Header="Find all references" Click="MenuItem_FindAllReferences_Click" Name="FindAllReferences"/>
-            <MenuItem Header="Copy name to clipboard" Click="MenuItem_CopyName_Click"/>
-            <MenuItem Header="Delete" Click="MenuItem_Delete_Click"/>
+            <MenuItem Header="{loc:Loc Common_OpenInNewTab}" Click="MenuItem_OpenInNewTab_Click"/>
+            <MenuItem Header="{loc:Loc FindRef_FindAllReferences}" Click="MenuItem_FindAllReferences_Click" Name="FindAllReferences"/>
+            <MenuItem Header="{loc:Loc FindRef_CopyNameToClipboard}" Click="MenuItem_CopyName_Click"/>
+            <MenuItem Header="{loc:Loc Common_Delete}" Click="MenuItem_Delete_Click"/>
         </local:ContextMenuDark>
 
-        <!-- TODO: Would need some way to know the ID, IndexOf won't be reliable -->
         <local:ContextMenuDark x:Key="NullItemReplaceMenu" Opened="MenuItem_NullDataContext_ContextMenuOpened">
-            <!--<MenuItem IsEnabled="False" Header="ID: " Name="ObjectIdLabel" />
-            <Separator />-->
-            <MenuItem IsEnabled="False" Header="Add in place (unimplemented)" />
+            <MenuItem IsEnabled="False" Header="{loc:Loc Ctrl_AddInPlaceUnimplemented}" />
         </local:ContextMenuDark>
 
         <Style x:Key="UndertaleModTool.ResourceListTreeViewItem.ItemContainerStyle" TargetType="{x:Type TreeViewItem}" BasedOn="{StaticResource {x:Type TreeViewItem}}">

diff --git a/UndertaleModTool/Controls/ResourceListTreeViewItem.xaml.cs b/UndertaleModTool/Controls/ResourceListTreeViewItem.xaml.cs
@@ -3,6 +3,7 @@
 using System.Windows;
 using System.Windows.Controls;
 using UndertaleModLib;
+using UndertaleModTool.Localization;
 using UndertaleModTool.Windows;
 using System.Linq;
 
@@ -96,7 +97,7 @@ private void MenuItem_FindAllReferences_Click(object sender, RoutedEventArgs e)
         {
             if ((sender as FrameworkElement)?.DataContext is not UndertaleResource obj)
             {
-                mainWindow.ShowError("The selected object is not an \"UndertaleResource\".");
+                mainWindow.ShowError(LocalizationSource.GetString("Msg_SelectedObjectNotUndertaleResource"));
                 return;
             }
 
@@ -108,8 +109,7 @@ private void MenuItem_FindAllReferences_Click(object sender, RoutedEventArgs e)
             }
             catch (Exception ex)
             {
-                mainWindow.ShowError("An error occured in the object references related window.\n" +
-                               $"Please report this on GitHub.\n\n{ex}");
+                mainWindow.ShowError(string.Format(LocalizationSource.GetString("Msg_ObjectReferencesWindowError"), ex));
             }
             finally
             {

diff --git a/UndertaleModTool/Controls/UndertaleObjectReference.xaml b/UndertaleModTool/Controls/UndertaleObjectReference.xaml
@@ -1,17 +1,18 @@
-<UserControl x:Class="UndertaleModTool.UndertaleObjectReference"
+<UserControl x:Class="UndertaleModTool.UndertaleObjectReference"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
-             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
              xmlns:local="clr-namespace:UndertaleModTool"
              xmlns:undertale="clr-namespace:UndertaleModLib.Models;assembly=UndertaleModLib"
-             mc:Ignorable="d" 
+             xmlns:loc="clr-namespace:UndertaleModTool.Localization"
+             mc:Ignorable="d"
              d:DesignHeight="20" d:DesignWidth="300"
              Name="objectReference">
     <UserControl.Resources>
         <local:ContextMenuDark x:Key="contextMenu" Opened="MenuItem_ContextMenuOpened">
-            <MenuItem Header="Open in new tab" Click="OpenInNewTabItem_Click"/>
-            <MenuItem Header="Find all references" Click="FindAllReferencesItem_Click"/>
+            <MenuItem Header="{loc:Loc Common_OpenInNewTab}" Click="OpenInNewTabItem_Click"/>
+            <MenuItem Header="{loc:Loc FindRef_FindAllReferences}" Click="FindAllReferencesItem_Click"/>
         </local:ContextMenuDark>
         <Label x:Key="emptyReferenceLabel" Foreground="Gray" FontStyle="Italic" />
     </UserControl.Resources>
@@ -28,7 +29,7 @@
                 <Style TargetType="{x:Type TextBox}">
                     <Style.Triggers>
                         <DataTrigger Binding="{Binding CanChange, ElementName=objectReference}" Value="True">
-                            <Setter Property="ToolTip" Value="This is an object reference. Drag and drop an object of matching type from the tree on the left to change it!" />
+                            <Setter Property="ToolTip" Value="{loc:Loc Ctrl_ObjRefToolTip}" />
                             <Setter Property="ToolTipService.InitialShowDelay" Value="250" />
                         </DataTrigger>
                         <DataTrigger Binding="{Binding ObjectReference, ElementName=objectReference}" Value="{x:Null}">
@@ -48,7 +49,7 @@
             <Button.Style>
                 <Style TargetType="{x:Type Button}">
                     <Setter Property="Content" Value=" ... " />
-                    <Setter Property="ToolTip" Value="Open referenced object" />
+                    <Setter Property="ToolTip" Value="{loc:Loc Ctrl_OpenReferencedObject}" />
                     <Style.Triggers>
                         <DataTrigger Binding="{Binding ObjectReference, ElementName=objectReference}" Value="{x:Null}">
                             <Setter Property="IsEnabled" Value="False"/>
@@ -60,14 +61,14 @@
                                 <Condition Binding="{Binding ObjectReference, ElementName=objectReference}" Value="{x:Null}" />
                             </MultiDataTrigger.Conditions>
                             <Setter Property="Content" Value=" + "/>
-                            <Setter Property="ToolTip" Value="Create new code entry" />
+                            <Setter Property="ToolTip" Value="{loc:Loc Ctrl_CreateNewCode}" />
                             <Setter Property="IsEnabled" Value="True"/>
                         </MultiDataTrigger>
                     </Style.Triggers>
                 </Style>
             </Button.Style>
         </local:ButtonDark>
-        <local:ButtonDark Grid.Column="2" x:Name="RemoveButton" Click="Remove_Click" Content=" X " ToolTip="Remove reference">
+        <local:ButtonDark Grid.Column="2" x:Name="RemoveButton" Click="Remove_Click" Content=" X " ToolTip="{loc:Loc Ctrl_RemoveReference}">
             <Button.Style>
                 <Style TargetType="{x:Type Button}">
                     <Style.Triggers>
@@ -86,4 +87,4 @@
             </Button.Style>
         </local:ButtonDark>
     </Grid>
-</UserControl>
+</UserControl>
diff --git a/UndertaleModTool/Controls/UndertaleObjectReference.xaml.cs b/UndertaleModTool/Controls/UndertaleObjectReference.xaml.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics;
@@ -18,6 +18,7 @@
 using UndertaleModLib;
 using UndertaleModLib.Models;
 using UndertaleModLib.Scripting;
+using UndertaleModTool.Localization;
 using UndertaleModTool.Windows;
 
 namespace UndertaleModTool
@@ -198,9 +199,9 @@ private void UndertaleObjectReference_Loaded(object sender, RoutedEventArgs e)
                 n = "n";
 
             if (CanChange)
-                label.Content = $"(drag & drop a{n} {typeName})";
+                label.Content = string.Format(LocalizationSource.GetString("Msg_DragDropAType"), n, typeName);
             else
-                label.Content = $"(empty {typeName} reference)";
+                label.Content = string.Format(LocalizationSource.GetString("Msg_EmptyTypeReference"), typeName);
         }
 
         public void ClearRemoveClickHandler()
@@ -310,7 +311,7 @@ private void FindAllReferencesItem_Click(object sender, RoutedEventArgs e)
             var obj = (sender as FrameworkElement)?.DataContext;
             if (obj is not UndertaleResource res)
             {
-                mainWindow.ShowError("The selected object is not an \"UndertaleResource\".");
+                mainWindow.ShowError(LocalizationSource.GetString("Msg_SelectedObjectNotUndertaleResource"));
                 return;
             }
 
@@ -322,8 +323,7 @@ private void FindAllReferencesItem_Click(object sender, RoutedEventArgs e)
             }
             catch (Exception ex)
             {
-                mainWindow.ShowError("An error occurred in the object references related window.\n" +
-                                     $"Please report this on GitHub.\n\n{ex}");
+                mainWindow.ShowError(string.Format(LocalizationSource.GetString("Msg_ObjectReferencesWindowError"), ex));
             }
             finally
             {

diff --git a/UndertaleModTool/Controls/UndertaleRoomRenderer.xaml.cs b/UndertaleModTool/Controls/UndertaleRoomRenderer.xaml.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Globalization;
@@ -19,6 +19,7 @@
 using System.Windows.Threading;
 using UndertaleModLib.Models;
 using static UndertaleModLib.Models.UndertaleRoom;
+using UndertaleModTool.Localization;
 
 namespace UndertaleModTool
 {
@@ -128,7 +129,7 @@ public class RoomCaptionConverter : IValueConverter
         public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
             UndertaleRoom room = value as UndertaleRoom;
-            return room is not null ? $"{room.Name.Content}: {room.Width}x{room.Height}" : "null";
+            return room is not null ? string.Format(LocalizationSource.GetString("Msg_RoomCaptionFormat"), room.Name.Content, room.Width, room.Height) : "null";
         }
         public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
         {