WPF的TabItem绑定属性

[番茄爱上蛋]

背景：
这几天我在修改工具时碰到一个TabItem绑定属性和改变样式的问题。该工具以前TabControl的TabItem是写死的，现在我想将TabControl的ItemsSource绑定给后台的一个动态List。然而因为TabControl绑定的是一个自定义类CalWindow的List，TabItem 中的Header属性必须绑定这个类中的WindowName属性，所以我必须修改TabControl的itemTemplate。改完之后TabControl显示样式就各种不对劲，虽然这些样式问题可以重写样式来实现，但是我担心只是我之前的写法有问题才会这么麻烦。麻烦大佬们看看问题出在哪吧，非常感谢。

代码：

MainWindow：

<Window x:Class="TabItemStyle.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:TabItemStyle"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <TabControl Height="37"  HorizontalAlignment="Left" Margin="47,31,0,0" Name="tabControl1" VerticalAlignment="Top" Background="#FF38474E" ItemsSource="{Binding gWindowList}" SelectedItem="{Binding gCurrentWindow}">
            <TabControl.ItemTemplate>
                <DataTemplate>
                    <TextBlock FontFamily="Arial" Background="#FF38474E"  FontWeight="Bold" Foreground="Black" FontSize="20" Padding="0" Text="{Binding WindowName}" />
                </DataTemplate>
            </TabControl.ItemTemplate>
        </TabControl>
    </Grid>
</Window>

MainWindowViewModel：

using Microsoft.Practices.Prism.ViewModel;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TabItemStyle
{
    public class MainWindowViewModel : NotificationObject
    {
        public MainWindowViewModel()
        {
            gWindowList = new ObservableCollection<CalWindow>
            {
                new CalWindow { WindowName = "September"},
                new CalWindow { WindowName = "December"},
                new CalWindow { WindowName = "June"},
                new CalWindow { WindowName = "November"}
            };
        }

        private ObservableCollection<CalWindow> _windowList = null;
        public ObservableCollection<CalWindow> gWindowList
        {
            get
            {
                return _windowList;
            }
            set
            {
                _windowList = value;
                this.RaisePropertyChanged(() => this.gWindowList);

                if (_windowList != null)
                {
                    gCurrentWindow = _windowList.First();
                }
            }
        }

        private CalWindow _currentWindow = null;
        public CalWindow gCurrentWindow
        {
            get
            {
                return _currentWindow;
            }
            set
            {
                _currentWindow = value;
                this.RaisePropertyChanged(() => this.gCurrentWindow);
            }
        }
    }
}

CalWindow：

using System.Text;
using System.Threading.Tasks;

namespace TabItemStyle
{
    public class CalWindow : NotificationObject
    {
        private string _windowName = "Unknown";
        public string WindowName
        {
            get
            {
                return _windowName;
            }
            set
            {
                if (_windowName != value)
                {
                    _windowName = value;
                    this.RaisePropertyChanged(() => this.WindowName);
                }
            }
        }
    }
}