Slight improvement on conversation chat box

Author: golf1052

Signal-Windows/Controls/Conversation.xaml

@@ -27,7 +27,7 @@
         <Grid.RowDefinitions>
             <RowDefinition Height="50" />
             <RowDefinition Height="*" />
-            <RowDefinition Height="50" />
+            <RowDefinition Height="Auto" />
         </Grid.RowDefinitions>
         <Border Grid.Row="0" Background="{x:Bind HeaderBackground, Mode=OneWay}">
             <StackPanel Grid.Row="0" Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center">
@@ -50,8 +50,8 @@
                 <ColumnDefinition Width="*"/>
                 <ColumnDefinition Width="Auto"/>
             </Grid.ColumnDefinitions>
-            <TextBox Grid.Column="0" Name="InputTextBox" VerticalAlignment="Center" KeyDown="TextBox_KeyDown" PlaceholderText="Type a message" BorderBrush="{x:Null}" BorderThickness="0"/>
-            <Button x:Name="SendMessageButton" Grid.Column="1" Click="SendMessageButton_Click" IsEnabled="{x:Bind SendEnabled, Mode=OneWay}" Background="{x:Bind HeaderBackground}" VerticalAlignment="Center" Width="50" Height="49">
+            <TextBox Grid.Column="0" Name="InputTextBox" VerticalAlignment="Center" KeyDown="TextBox_KeyDown" PlaceholderText="Type a message" BorderBrush="{x:Null}" BorderThickness="0" TextWrapping="Wrap" TextChanged="InputTextBox_TextChanged"/>
+            <Button x:Name="SendMessageButton" Grid.Column="1" Click="SendMessageButton_Click" IsEnabled="{x:Bind SendEnabled, Mode=OneWay}" Background="{x:Bind HeaderBackground}" VerticalAlignment="Bottom" Width="50" VerticalContentAlignment="Stretch" MinHeight="50">
                 <SymbolIcon Symbol="Send"/>
             </Button>
         </Grid>

Signal-Windows/Controls/Conversation.xaml.cs

@@ -216,8 +216,6 @@ public void AddToOutgoingMessagesCache(SignalMessage sm)
 
         private async void TextBox_KeyDown(object sender, KeyRoutedEventArgs e)
         {
-            TextBox t = sender as TextBox;
-            SendEnabled = t.Text != string.Empty;
             if (e.Key == Windows.System.VirtualKey.Enter)
             {
                 // this fixes double send by enter repeat
@@ -243,6 +241,12 @@ private async void SendMessageButton_Click(object sender, RoutedEventArgs e)
         {
             await GetMainPageVm().SendMessageButton_Click(InputTextBox);
         }
+
+        private void InputTextBox_TextChanged(object sender, TextChangedEventArgs e)
+        {
+            TextBox t = sender as TextBox;
+            SendEnabled = t.Text != string.Empty;
+        }
     }
 
     public class SignalUnreadMarker