Multiple Changes:

DXA8 now directly asks for password, as guessing it, is made improbable.
Promote several private methods to `protected` status
Add code for indexing DXA8 files. (not finished)

ArcFormats/DxLib/WidgetDXA.xaml

@@ -0,0 +1,19 @@
+<StackPanel x:Class="GameRes.Formats.GUI.WidgetDXA"
+             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:GameRes.Formats.DxLib"
+             mc:Ignorable="d" 
+            
+            xmlns:s="clr-namespace:GameRes.Formats.Strings"
+            xmlns:p="clr-namespace:GameRes.Formats.Properties"
+            xmlns:dxa="clr-namespace:GameRes.Formats.DxLib">
+    <Label Content="{x:Static s:arcStrings.ArcTitleOrPassword}" HorizontalAlignment="Left"/>
+    <ComboBox Name="Title" Width="200" HorizontalAlignment="Left"
+          ItemsSource="{Binding RelativeSource={RelativeSource Self}, Path=DataContext}"
+          SelectedValue="{Binding ElementName=Password, Path=Text, Mode=TwoWay}" SelectedValuePath="Value"
+          DisplayMemberPath="Key"/>
+    <TextBox x:Name="Password" Width="200" HorizontalAlignment="Left" Margin="0,5,0,0"
+         Text="{Binding Source={x:Static p:Settings.Default}, Path=DXAPassword, Mode=OneWay}"/>
+</StackPanel>