diff --git a/Bloxstrap/Bloxstrap.csproj b/Bloxstrap/Bloxstrap.csproj
index 8598d98..9426fa2 100644
--- a/Bloxstrap/Bloxstrap.csproj
+++ b/Bloxstrap/Bloxstrap.csproj
@@ -31,7 +31,8 @@
 
   <ItemGroup>
     <EmbeddedResource Include="Resources\CustomBootstrapperSchema.json" />
-    <EmbeddedResource Include="Resources\CustomBootstrapperTemplate.xml" />
+    <EmbeddedResource Include="Resources\CustomBootstrapperTemplate_Blank.xml" />
+    <EmbeddedResource Include="Resources\CustomBootstrapperTemplate_Simple.xml" />
     <EmbeddedResource Include="Resources\Icon2008.ico" />
     <EmbeddedResource Include="Resources\Icon2011.ico" />
     <EmbeddedResource Include="Resources\Icon2017.ico" />
diff --git a/Bloxstrap/Enums/CustomThemeTemplate.cs b/Bloxstrap/Enums/CustomThemeTemplate.cs
new file mode 100644
index 0000000..6497907
--- /dev/null
+++ b/Bloxstrap/Enums/CustomThemeTemplate.cs
@@ -0,0 +1,8 @@
+namespace Bloxstrap.Enums
+{
+    public enum CustomThemeTemplate
+    {
+        Blank,
+        Simple
+    }
+}
diff --git a/Bloxstrap/Extensions/CustomThemeTemplateEx.cs b/Bloxstrap/Extensions/CustomThemeTemplateEx.cs
new file mode 100644
index 0000000..4088f02
--- /dev/null
+++ b/Bloxstrap/Extensions/CustomThemeTemplateEx.cs
@@ -0,0 +1,10 @@
+namespace Bloxstrap.Extensions
+{
+    static class CustomThemeTemplateEx
+    {
+        public static string GetFileName(this CustomThemeTemplate template)
+        {
+            return $"CustomBootstrapperTemplate_{template}.xml";
+        }
+    }
+}
diff --git a/Bloxstrap/Resources/CustomBootstrapperTemplate.xml b/Bloxstrap/Resources/CustomBootstrapperTemplate_Blank.xml
similarity index 100%
rename from Bloxstrap/Resources/CustomBootstrapperTemplate.xml
rename to Bloxstrap/Resources/CustomBootstrapperTemplate_Blank.xml
diff --git a/Bloxstrap/Resources/CustomBootstrapperTemplate_Simple.xml b/Bloxstrap/Resources/CustomBootstrapperTemplate_Simple.xml
new file mode 100644
index 0000000..1b3f534
--- /dev/null
+++ b/Bloxstrap/Resources/CustomBootstrapperTemplate_Simple.xml
@@ -0,0 +1,9 @@
+<BloxstrapCustomBootstrapper Version="0" Height="320" Width="520" IgnoreTitleBarInset="True" Theme="Default" Margin="30">
+	<!-- Find more custom bootstrapper examples at https://github.com/bloxstraplabs/custom-bootstrapper-examples -->
+	<TitleBar Title="" ShowMinimize="False" ShowClose="False" />
+
+	<Image Source="{Icon}" Height="100" Width="100" HorizontalAlignment="Center" Margin="0,15,0,0" />
+	<TextBlock HorizontalAlignment="Center" Name="StatusText" FontSize="20" Margin="0,170,0,0" />
+	<ProgressBar Width="450" Height="12" Name="PrimaryProgressBar" HorizontalAlignment="Center" Margin="0,200,0,0" />
+	<Button Content="Cancel" Name="CancelButton" HorizontalAlignment="Center" Margin="0,225,0,0" Height="30" Width="100" />
+</BloxstrapCustomBootstrapper>
\ No newline at end of file
diff --git a/Bloxstrap/Resources/Strings.Designer.cs b/Bloxstrap/Resources/Strings.Designer.cs
index a3b845e..93bbed5 100644
--- a/Bloxstrap/Resources/Strings.Designer.cs
+++ b/Bloxstrap/Resources/Strings.Designer.cs
@@ -1170,6 +1170,24 @@ namespace Bloxstrap.Resources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Blank.
+        /// </summary>
+        public static string Enums_CustomThemeTemplate_Blank {
+            get {
+                return ResourceManager.GetString("Enums.CustomThemeTemplate.Blank", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Simple.
+        /// </summary>
+        public static string Enums_CustomThemeTemplate_Simple {
+            get {
+                return ResourceManager.GetString("Enums.CustomThemeTemplate.Simple", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Catmoji.
         /// </summary>
diff --git a/Bloxstrap/Resources/Strings.resx b/Bloxstrap/Resources/Strings.resx
index 5e593cf..2261088 100644
--- a/Bloxstrap/Resources/Strings.resx
+++ b/Bloxstrap/Resources/Strings.resx
@@ -1273,4 +1273,10 @@ Please close any applications that may be using Roblox's files, and relaunch.</v
   <data name="Menu.About.Licenses.Apache" xml:space="preserve">
     <value>Apache License 2.0</value>
   </data>
+  <data name="Enums.CustomThemeTemplate.Blank" xml:space="preserve">
+    <value>Blank</value>
+  </data>
+  <data name="Enums.CustomThemeTemplate.Simple" xml:space="preserve">
+    <value>Simple</value>
+  </data>
 </root>
\ No newline at end of file
diff --git a/Bloxstrap/UI/Elements/Dialogs/AddCustomThemeDialog.xaml b/Bloxstrap/UI/Elements/Dialogs/AddCustomThemeDialog.xaml
new file mode 100644
index 0000000..47f3a01
--- /dev/null
+++ b/Bloxstrap/UI/Elements/Dialogs/AddCustomThemeDialog.xaml
@@ -0,0 +1,165 @@
+<base:WpfUiWindow
+    x:Class="Bloxstrap.UI.Elements.Dialogs.AddCustomThemeDialog"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:base="clr-namespace:Bloxstrap.UI.Elements.Base"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:local="clr-namespace:Bloxstrap.UI.Elements.Dialogs"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:resources="clr-namespace:Bloxstrap.Resources"
+    xmlns:ui="http://schemas.lepo.co/wpfui/2022/xaml"
+    xmlns:viewmodels="clr-namespace:Bloxstrap.UI.ViewModels.Dialogs"
+    Title="Add Custom Theme"
+    Width="480"
+    MinHeight="0"
+    d:DataContext="{d:DesignInstance viewmodels:AddCustomThemeViewModel,
+                                     IsDesignTimeCreatable=True}"
+    Background="{ui:ThemeResource ApplicationBackgroundBrush}"
+    ExtendsContentIntoTitleBar="True"
+    ResizeMode="NoResize"
+    SizeToContent="Height"
+    WindowStartupLocation="CenterScreen"
+    mc:Ignorable="d">
+    <Grid>
+        <Grid>
+            <Grid.RowDefinitions>
+                <RowDefinition Height="Auto" />
+                <RowDefinition Height="*" />
+                <RowDefinition Height="Auto" />
+            </Grid.RowDefinitions>
+
+            <ui:TitleBar
+                Title="Add Custom Theme"
+                Grid.Row="0"
+                Grid.ColumnSpan="2"
+                Padding="8"
+                CanMaximize="False"
+                KeyboardNavigation.TabNavigation="None"
+                ShowMaximize="False"
+                ShowMinimize="False" />
+
+            <TabControl
+                x:Name="Tabs"
+                Grid.Row="1"
+                Margin="16"
+                SelectedIndex="{Binding Path=SelectedTab, Mode=TwoWay}">
+                <TabItem Header="Create New">
+                    <Grid Grid.Row="1" Margin="16">
+                        <Grid.RowDefinitions>
+                            <RowDefinition Height="Auto" />
+                            <RowDefinition Height="Auto" />
+                        </Grid.RowDefinitions>
+                        <Grid.ColumnDefinitions>
+                            <ColumnDefinition Width="Auto" />
+                            <ColumnDefinition Width="*" />
+                        </Grid.ColumnDefinitions>
+
+                        <Grid
+                            Grid.Row="0"
+                            Grid.ColumnSpan="2"
+                            Margin="0,0,0,12">
+                            <Grid.RowDefinitions>
+                                <RowDefinition Height="Auto" />
+                                <RowDefinition Height="Auto" />
+                            </Grid.RowDefinitions>
+                            <Grid.ColumnDefinitions>
+                                <ColumnDefinition Width="Auto" />
+                                <ColumnDefinition Width="*" />
+                            </Grid.ColumnDefinitions>
+
+                            <TextBlock
+                                Grid.Row="0"
+                                Grid.Column="0"
+                                MinWidth="100"
+                                VerticalAlignment="Center"
+                                Text="{x:Static resources:Strings.Common_Name}" />
+                            <TextBox
+                                Grid.Row="0"
+                                Grid.Column="1"
+                                Text="{Binding Path=Name, Mode=TwoWay}" />
+
+                            <TextBlock
+                                Grid.Row="1"
+                                Grid.Column="1"
+                                Foreground="{DynamicResource SystemFillColorCriticalBrush}"
+                                Text="{Binding Path=NameError, Mode=OneWay}"
+                                TextAlignment="Center"
+                                TextWrapping="Wrap"
+                                Visibility="{Binding Path=NameErrorVisibility, Mode=OneWay}" />
+                        </Grid>
+
+                        <TextBlock
+                            Grid.Row="1"
+                            Grid.Column="0"
+                            MinWidth="100"
+                            VerticalAlignment="Center"
+                            Text="Template" />
+
+                        <ComboBox
+                            Grid.Row="1"
+                            Grid.Column="1"
+                            ItemsSource="{Binding Path=Templates, Mode=OneTime}"
+                            Text="{Binding Path=Template, Mode=TwoWay}">
+                            <ComboBox.ItemTemplate>
+                                <DataTemplate>
+                                    <TextBlock Text="{Binding Path=., Converter={StaticResource EnumNameConverter}}" />
+                                </DataTemplate>
+                            </ComboBox.ItemTemplate>
+                        </ComboBox>
+                    </Grid>
+                </TabItem>
+                <TabItem Header="Import">
+                    <Grid Margin="11">
+                        <Grid.RowDefinitions>
+                            <RowDefinition Height="*" />
+                            <RowDefinition Height="*" />
+                            <RowDefinition Height="*" />
+                        </Grid.RowDefinitions>
+                        <TextBlock
+                            Grid.Row="0"
+                            FontSize="14"
+                            Text="{Binding Path=FilePath}"
+                            TextAlignment="Center"
+                            TextWrapping="Wrap"
+                            Visibility="{Binding Path=FilePathVisibility}" />
+                        <ui:Button
+                            Grid.Row="1"
+                            Margin="4"
+                            HorizontalAlignment="Stretch"
+                            Click="OnImportButtonClicked"
+                            Content="{x:Static resources:Strings.Common_ImportFromFile}"
+                            Icon="DocumentArrowUp16" />
+                        <TextBlock
+                            Grid.Row="2"
+                            Foreground="{DynamicResource SystemFillColorCriticalBrush}"
+                            Text="{Binding Path=FileError}"
+                            TextAlignment="Center"
+                            TextWrapping="Wrap"
+                            Visibility="{Binding Path=FileErrorVisibility}" />
+                    </Grid>
+                </TabItem>
+            </TabControl>
+
+            <Border
+                Grid.Row="2"
+                Margin="0,10,0,0"
+                Padding="15"
+                Background="{ui:ThemeResource SolidBackgroundFillColorSecondaryBrush}">
+                <StackPanel
+                    HorizontalAlignment="Right"
+                    FlowDirection="LeftToRight"
+                    Orientation="Horizontal">
+                    <Button
+                        MinWidth="100"
+                        Click="OnOkButtonClicked"
+                        Content="{x:Static resources:Strings.Common_OK}" />
+                    <Button
+                        MinWidth="100"
+                        Margin="12,0,0,0"
+                        Content="{x:Static resources:Strings.Common_Cancel}"
+                        IsCancel="True" />
+                </StackPanel>
+            </Border>
+        </Grid>
+    </Grid>
+</base:WpfUiWindow>
diff --git a/Bloxstrap/UI/Elements/Dialogs/AddCustomThemeDialog.xaml.cs b/Bloxstrap/UI/Elements/Dialogs/AddCustomThemeDialog.xaml.cs
new file mode 100644
index 0000000..6358ac4
--- /dev/null
+++ b/Bloxstrap/UI/Elements/Dialogs/AddCustomThemeDialog.xaml.cs
@@ -0,0 +1,230 @@
+using Bloxstrap.UI.Elements.Base;
+using Bloxstrap.UI.ViewModels.Dialogs;
+using Microsoft.Win32;
+using System.IO.Compression;
+using System.Windows;
+
+namespace Bloxstrap.UI.Elements.Dialogs
+{
+    /// <summary>
+    /// Interaction logic for AddCustomThemeDialog.xaml
+    /// </summary>
+    public partial class AddCustomThemeDialog : WpfUiWindow
+    {
+        private const int CreateNewTabId = 0;
+        private const int ImportTabId = 1;
+
+        private readonly AddCustomThemeViewModel _viewModel;
+
+        public bool Created { get; private set; } = false;
+        public string ThemeName { get; private set; } = "";
+        public bool OpenEditor { get; private set; } = false;
+
+        public AddCustomThemeDialog()
+        {
+            _viewModel = new AddCustomThemeViewModel();
+            _viewModel.Name = GenerateRandomName();
+
+            DataContext = _viewModel;
+
+            InitializeComponent();
+        }
+
+        private static string GetThemePath(string name)
+        {
+            return Path.Combine(Paths.CustomThemes, name, "Theme.xml");
+        }
+
+        private static string GenerateRandomName()
+        {
+            int count = Directory.GetDirectories(Paths.CustomThemes).Count();
+
+            string name = $"Custom Theme {count + 1}";
+
+            // TODO: this sucks
+            if (File.Exists(GetThemePath(name)))
+                name += " " + Random.Shared.Next(1, 100000).ToString(); // easy
+
+            return name;
+        }
+
+        private static string GetUniqueName(string name)
+        {
+            const int maxTries = 100;
+
+            if (!File.Exists(GetThemePath(name)))
+                return name;
+
+            for (int i = 1; i <= maxTries; i++)
+            {
+                string newName = $"{name}_{i}";
+                if (!File.Exists(GetThemePath(newName)))
+                    return newName;
+            }
+
+            // last resort
+            return $"{name}_{Random.Shared.Next(maxTries+1, 1_000_000)}";
+        }
+
+        private static void CreateCustomTheme(string name, CustomThemeTemplate template)
+        {
+            string dir = Path.Combine(Paths.CustomThemes, name);
+
+            if (Directory.Exists(dir))
+                Directory.Delete(dir, true);
+            Directory.CreateDirectory(dir);
+
+            string themeFilePath = Path.Combine(dir, "Theme.xml");
+
+            string templateContent = Encoding.UTF8.GetString(Resource.Get(template.GetFileName()).Result);
+
+            File.WriteAllText(themeFilePath, templateContent);
+        }
+
+        private bool ValidateCreateNew()
+        {
+            const string LOG_IDENT = "AddCustomThemeDialog::ValidateCreateNew";
+
+            if (string.IsNullOrEmpty(_viewModel.Name))
+            {
+                _viewModel.NameError = "Name cannot be empty";
+                return false;
+            }
+
+            var validationResult = PathValidator.IsFileNameValid(_viewModel.Name);
+
+            if (validationResult != PathValidator.ValidationResult.Ok)
+            {
+                switch (validationResult)
+                {
+                    case PathValidator.ValidationResult.IllegalCharacter:
+                        _viewModel.NameError = "Name contains illegal characters";
+                        break;
+                    case PathValidator.ValidationResult.ReservedFileName:
+                        _viewModel.NameError = "Name cannot be used";
+                        break;
+                    default:
+                        App.Logger.WriteLine(LOG_IDENT, $"Got unhandled PathValidator::ValidationResult {validationResult}");
+                        Debug.Assert(false);
+
+                        _viewModel.NameError = "Unknown error";
+                        break;
+                }
+
+                return false;
+            }
+
+            // better to check for the file instead of the directory so broken themes can be overwritten
+            string path = Path.Combine(Paths.CustomThemes, _viewModel.Name, "Theme.xml");
+            if (File.Exists(path))
+            {
+                _viewModel.NameError = "Name is already in use";
+                return false;
+            }    
+
+            return true;
+        }
+
+        private bool ValidateImport()
+        {
+            const string LOG_IDENT = "AddCustomThemeDialog::ValidateImport";
+
+            if (!_viewModel.FilePath.EndsWith(".zip"))
+            {
+                _viewModel.FileError = "File must be a ZIP";
+                return false;
+            }
+
+            try
+            {
+                using var zipFile = ZipFile.OpenRead(_viewModel.FilePath);
+                var entries = zipFile.Entries;
+
+                bool foundThemeFile = false;
+
+                foreach (var entry in entries)
+                {
+                    if (entry.FullName == "Theme.xml")
+                    {
+                        foundThemeFile = true;
+                        break;
+                    }
+                }
+
+                if (!foundThemeFile)
+                {
+                    _viewModel.FileError = "Theme file could not be found in the ZIP file";
+                    return false;
+                }
+
+                return true;
+            }
+            catch (InvalidDataException ex)
+            {
+                App.Logger.WriteLine(LOG_IDENT, "Got invalid data");
+                App.Logger.WriteException(LOG_IDENT, ex);
+
+                _viewModel.FileError = "Invalid or corrupted ZIP file";
+                return false;
+            }
+        }
+
+        private void CreateNew()
+        {
+            if (!ValidateCreateNew())
+                return;
+
+            CreateCustomTheme(_viewModel.Name, _viewModel.Template);
+
+            Created = true;
+            ThemeName = _viewModel.Name;
+            OpenEditor = true;
+
+            Close();
+        }
+
+        private void Import()
+        {
+            if (!ValidateImport())
+                return;
+
+            string fileName = Path.GetFileNameWithoutExtension(_viewModel.FilePath);
+            string name = GetUniqueName(fileName);
+
+            string directory = Path.Combine(Paths.CustomThemes, name);
+            if (Directory.Exists(directory))
+                Directory.Delete(directory, true);
+            Directory.CreateDirectory(directory);
+
+            var fastZip = new ICSharpCode.SharpZipLib.Zip.FastZip();
+            fastZip.ExtractZip(_viewModel.FilePath, directory, null);
+
+            Created = true;
+            ThemeName = name;
+            OpenEditor = false;
+
+            Close();
+        }
+
+        private void OnOkButtonClicked(object sender, RoutedEventArgs e)
+        {
+            if (_viewModel.SelectedTab == CreateNewTabId)
+                CreateNew();
+            else
+                Import();
+        }
+
+        private void OnImportButtonClicked(object sender, RoutedEventArgs e)
+        {
+            var dialog = new OpenFileDialog
+            {
+                Filter = $"{Strings.FileTypes_ZipArchive}|*.zip"
+            };
+
+            if (dialog.ShowDialog() != true)
+                return;
+
+            _viewModel.FilePath = dialog.FileName;
+        }
+    }
+}
diff --git a/Bloxstrap/UI/ViewModels/Dialogs/AddCustomThemeViewModel.cs b/Bloxstrap/UI/ViewModels/Dialogs/AddCustomThemeViewModel.cs
new file mode 100644
index 0000000..ec4282d
--- /dev/null
+++ b/Bloxstrap/UI/ViewModels/Dialogs/AddCustomThemeViewModel.cs
@@ -0,0 +1,68 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows;
+
+namespace Bloxstrap.UI.ViewModels.Dialogs
+{
+    internal class AddCustomThemeViewModel : NotifyPropertyChangedViewModel
+    {
+        public static CustomThemeTemplate[] Templates => Enum.GetValues<CustomThemeTemplate>();
+
+        public CustomThemeTemplate Template { get; set; } = CustomThemeTemplate.Simple;
+
+        public string Name { get; set; } = "";
+
+        private string _filePath = "";
+        public string FilePath
+        {
+            get => _filePath;
+            set
+            {
+                if (_filePath != value)
+                {
+                    _filePath = value;
+                    OnPropertyChanged(nameof(FilePath));
+                    OnPropertyChanged(nameof(FilePathVisibility));
+                }
+            }
+        }
+        public Visibility FilePathVisibility => string.IsNullOrEmpty(FilePath) ? Visibility.Collapsed : Visibility.Visible;
+
+        public int SelectedTab { get; set; } = 0;
+
+        private string _nameError = "";
+        public string NameError
+        {
+            get => _nameError;
+            set
+            {
+                if (_nameError != value)
+                {
+                    _nameError = value;
+                    OnPropertyChanged(nameof(NameError));
+                    OnPropertyChanged(nameof(NameErrorVisibility));
+                }
+            }
+        }
+        public Visibility NameErrorVisibility => string.IsNullOrEmpty(NameError) ? Visibility.Collapsed : Visibility.Visible;
+
+        private string _fileError = "";
+        public string FileError
+        {
+            get => _fileError;
+            set
+            {
+                if (_fileError != value)
+                {
+                    _fileError = value;
+                    OnPropertyChanged(nameof(FileError));
+                    OnPropertyChanged(nameof(FileErrorVisibility));
+                }
+            }
+        }
+        public Visibility FileErrorVisibility => string.IsNullOrEmpty(FileError) ? Visibility.Collapsed : Visibility.Visible;
+    }
+}
diff --git a/Bloxstrap/UI/ViewModels/Settings/AppearanceViewModel.cs b/Bloxstrap/UI/ViewModels/Settings/AppearanceViewModel.cs
index e8666d5..1f5f359 100644
--- a/Bloxstrap/UI/ViewModels/Settings/AppearanceViewModel.cs
+++ b/Bloxstrap/UI/ViewModels/Settings/AppearanceViewModel.cs
@@ -9,6 +9,8 @@ using Microsoft.Win32;
 
 using Bloxstrap.UI.Elements.Settings;
 using Bloxstrap.UI.Elements.Editor;
+using Bloxstrap.UI.Elements.Dialogs;
+using System.Xml.Linq;
 
 namespace Bloxstrap.UI.ViewModels.Settings
 {
@@ -131,31 +133,6 @@ namespace Bloxstrap.UI.ViewModels.Settings
             }
         }
 
-        private string CreateCustomThemeName()
-        {
-            int count = Directory.GetDirectories(Paths.CustomThemes).Count();
-
-            string name = $"Custom Theme {count + 1}";
-
-            // TODO: this sucks
-            if (Directory.Exists(Path.Combine(Paths.CustomThemes, name))) // DUCK
-                name += " " + Random.Shared.Next(1, 100000).ToString(); // easy
-
-            return name;
-        }
-
-        private void CreateCustomThemeStructure(string name)
-        {
-            string dir = Path.Combine(Paths.CustomThemes, name);
-            Directory.CreateDirectory(dir);
-
-            string themeFilePath = Path.Combine(dir, "Theme.xml");
-
-            string templateContent = Encoding.UTF8.GetString(Resource.Get("CustomBootstrapperTemplate.xml").Result);
-
-            File.WriteAllText(themeFilePath, templateContent);
-        }
-
         private void DeleteCustomThemeStructure(string name)
         {
             string dir = Path.Combine(Paths.CustomThemes, name);
@@ -171,24 +148,20 @@ namespace Bloxstrap.UI.ViewModels.Settings
 
         private void AddCustomTheme()
         {
-            string name = CreateCustomThemeName();
+            var dialog = new AddCustomThemeDialog();
+            dialog.ShowDialog();
 
-            try
+            if (dialog.Created)
             {
-                CreateCustomThemeStructure(name);
-            }
-            catch (Exception ex)
-            {
-                App.Logger.WriteException("AppearanceViewModel::AddCustomTheme", ex);
-                Frontend.ShowMessageBox($"Failed to create custom theme: {ex.Message}", MessageBoxImage.Error);
-                return;
-            }
+                CustomThemes.Add(dialog.ThemeName);
+                SelectedCustomThemeIndex = CustomThemes.Count - 1;
 
-            CustomThemes.Add(name);
-            SelectedCustomThemeIndex = CustomThemes.Count - 1;
+                OnPropertyChanged(nameof(SelectedCustomThemeIndex));
+                OnPropertyChanged(nameof(IsCustomThemeSelected));
 
-            OnPropertyChanged(nameof(SelectedCustomThemeIndex));
-            OnPropertyChanged(nameof(IsCustomThemeSelected));
+                if (dialog.OpenEditor)
+                    EditCustomTheme();
+            }
         }
 
         private void DeleteCustomTheme()
diff --git a/Bloxstrap/Utility/PathValidator.cs b/Bloxstrap/Utility/PathValidator.cs
new file mode 100644
index 0000000..024ed09
--- /dev/null
+++ b/Bloxstrap/Utility/PathValidator.cs
@@ -0,0 +1,104 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Bloxstrap.Utility
+{
+    internal static class PathValidator
+    {
+        public enum ValidationResult
+        {
+            Ok,
+            IllegalCharacter,
+            ReservedFileName,
+            ReservedDirectoryName
+        }
+
+        private static readonly string[] _reservedNames = new string[]
+        {
+            "CON",
+            "PRN",
+            "AUX",
+            "NUL",
+            "COM1",
+            "COM2",
+            "COM3",
+            "COM4",
+            "COM5",
+            "COM6",
+            "COM7",
+            "COM8",
+            "COM9",
+            "LPT1",
+            "LPT2",
+            "LPT3",
+            "LPT4",
+            "LPT5",
+            "LPT6",
+            "LPT7",
+            "LPT8",
+            "LPT9"
+        };
+
+        private static readonly char[] _directorySeperatorDelimiters = new char[]
+        {
+            Path.DirectorySeparatorChar,
+            Path.AltDirectorySeparatorChar
+        };
+
+        private static readonly char[] _invalidPathChars = GetInvalidPathChars();
+
+        public static char[] GetInvalidPathChars()
+        {
+            char[] invalids = new char[] { '/', '\\', ':', '*', '?', '"', '<', '>', '|' };
+            char[] otherInvalids = Path.GetInvalidPathChars();
+
+            char[] result = new char[invalids.Length + otherInvalids.Length];
+            invalids.CopyTo(result, 0);
+            otherInvalids.CopyTo(result, invalids.Length);
+
+            return result;
+        }
+
+        public static ValidationResult IsFileNameValid(string fileName)
+        {
+            if (fileName.IndexOfAny(_invalidPathChars) != -1)
+                return ValidationResult.IllegalCharacter;
+
+            string fileNameNoExt = Path.GetFileNameWithoutExtension(fileName).ToUpperInvariant();
+            if (_reservedNames.Contains(fileNameNoExt))
+                return ValidationResult.ReservedFileName;
+
+            return ValidationResult.Ok;
+        }
+
+        public static ValidationResult IsPathValid(string path)
+        {
+            string? pathRoot = Path.GetPathRoot(path);
+            string pathNoRoot = pathRoot != null ? path[pathRoot.Length..] : path;
+
+            string[] pathParts = pathNoRoot.Split(_directorySeperatorDelimiters);
+
+            foreach (var part in pathParts)
+            {
+                if (part.IndexOfAny(_invalidPathChars) != -1)
+                    return ValidationResult.IllegalCharacter;
+
+                if (_reservedNames.Contains(part))
+                    return ValidationResult.ReservedDirectoryName;
+            }
+
+            string fileName = Path.GetFileName(path);
+            if (fileName.IndexOfAny(_invalidPathChars) != -1)
+                return ValidationResult.IllegalCharacter;
+
+            string fileNameNoExt = Path.GetFileNameWithoutExtension(path).ToUpperInvariant();
+            if (_reservedNames.Contains(fileNameNoExt))
+                return ValidationResult.ReservedFileName;
+
+            return ValidationResult.Ok;
+        }
+    }
+}