Make WPF element responsive on the height and fix some glitches?

I choose WPF as GUI toolkit as the application will run on Windows only.

My actual code:

MainWindow.xaml.cs

public MainWindow()
{
    InitializeComponent();

    List<Task> tasks = new List<Task>();
    tasks.Add(new Task() { Selected = false, Name = "Task Name #01", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask01" });
    tasks.Add(new Task() { Selected = false, Name = "Task Name #02", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask02" });
    tasks.Add(new Task() { Selected = false, Name = "Task Name #03", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask03" });
    tasks.Add(new Task() { Selected = false, Name = "Task Name #04", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask04" });
    tasks.Add(new Task() { Selected = false, Name = "Task Name #05", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask05" });
    tasks.Add(new Task() { Selected = false, Name = "Task Name #06", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask06" });
    tasks.Add(new Task() { Selected = false, Name = "Task Name #07", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask07" });
    tasks.Add(new Task() { Selected = false, Name = "Task Name #08", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask08" });
    tasks.Add(new Task() { Selected = false, Name = "Task Name #09", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask09" });
    tasks.Add(new Task() { Selected = false, Name = "Task Name #10", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask10" });
    tasks.Add(new Task() { Selected = false, Name = "Task Name #11", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask11" });
    tasks.Add(new Task() { Selected = false, Name = "Task Name #12", Priority = "Urgent", Description = "Lorem ipsum", Run = "RunTask12" });

    dgTask.ItemsSource = tasks;
}

public class Task
{
    public bool Selected { get; set; }
    public string Name { get; set; }
    public string Priority { get; set; }
    public string Description { get; set; }
    public string Run { get; set; }
}

MainWindow.xaml

<Window x:Class="SpeechlessBeta.MainWindow"
        xmlns="http://ift.tt/o66D3f"
        xmlns:x="http://ift.tt/mPTqtT"
        Title="MainWindow" Height="320" Width="500">
    <Grid Margin="5">
        <DockPanel LastChildFill="True">
            <DataGrid DockPanel.Dock="Top" Margin="0,0,0,5" Name="dgTask"/>
            <Button Height="24" Margin="5,0,0,0" Padding="15,0" Content="Btn2" DockPanel.Dock="Right"/>
            <Button Height="24" Margin="5,0,0,0" Padding="15,0" Content="Btn1" DockPanel.Dock="Right"/>
            <ProgressBar Height="24"/>
        </DockPanel>
    </Grid>
</Window>

This is the result I want (mockup):

http://ift.tt/1EfXigD

But this is what I've got:

http://ift.tt/1DyVV9u

The "Run" column should be hidden and corresponds to the method that will be executed if the checkbox is selected and if I press the button "Btn2".

Issues:

• The DataGrid is not responsive/fluid on the height at all.


• How to rename the first column or add an image as header?


• I don't know why I've got an empty column on the left...


• There is an empty row too...


• Why I need to click twice to select a checkbox? Can I change this behavior?