how to uncheck check box of datagrid column header

I am using two datagrid.first datagrid contains items with checkbox, upon checking checkbox corresponding data will appear in second datagrid(this datagrid column header and rows contains checkbox)

here when ever i am selecting another tab check and uncheck of previous tab is showing as it is.

For this on mousebuttonup event made first datagrid to default so uncheck of datagrid header column is happening but i could not do the same for second datagrid.what ever i do its showing(i want to make it second datagrid with default value)

Any idea to acheive this? please help me.

here is my xaml code<DataGrid Name="dgReport" HorizontalAlignment="Stretch"  VerticalAlignment="Stretch" BorderBrush="Black" BorderThickness="1 1 1 1" Margin="13,4,50,6" AutoGenerateColumns="False" CanUserAddRows="False" Grid.ColumnSpan="2"><DataGrid.Columns><DataGridTemplateColumn><!--<DataGridTemplateColumn.HeaderTemplate><DataTemplate><CheckBox Name="hchkInOutReport" Checked="hchkInOutReport_Checked" Unchecked="hchkInOutReport_Unchecked"></CheckBox></DataTemplate></DataGridTemplateColumn.HeaderTemplate>--><DataGridTemplateColumn.CellTemplate><DataTemplate><CheckBox Name="chkInOutReport" Width="50" Margin="4,0,0,0" IsChecked="{Binding Path=IsSelected, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"></CheckBox></DataTemplate></DataGridTemplateColumn.CellTemplate></DataGridTemplateColumn><DataGridTextColumn Binding="{Binding szCommonName }" Header="Department" Width="*"></DataGridTextColumn></DataGrid.Columns><!--<DataGrid.Columns><DataGridCheckBoxColumn><DataGridCheckBoxColumn.Header><CheckBox Name="chkbSelectDIOReport" IsChecked="False"/></DataGridCheckBoxColumn.Header></DataGridCheckBoxColumn><DataGridTextColumn Header="Department Name" Width="*"/></DataGrid.Columns>--></DataGrid><DataGrid Grid.Column="2" Name="dgDIOReport" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" BorderBrush="Black" BorderThickness="1 1 1 1" AutoGenerateColumns="False"  CanUserAddRows="False" Margin="0 10 10 0" Visibility="Hidden"><DataGrid.Columns><DataGridTemplateColumn><DataGridTemplateColumn.HeaderTemplate><DataTemplate><CheckBox Name="hchkInOutReportEmp" Checked="hchkInOutReportEmp_Checked" Unchecked="hchkInOutReportEmp_Unchecked"></CheckBox></DataTemplate></DataGridTemplateColumn.HeaderTemplate><DataGridTemplateColumn.CellTemplate><DataTemplate><CheckBox Name="chkInOutReportEmp" Width="50" Margin="4,0,0,0" IsChecked="{Binding Path=IsSelected, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" ></CheckBox></DataTemplate></DataGridTemplateColumn.CellTemplate></DataGridTemplateColumn><DataGridTextColumn Header="Serial No." Width="*" Binding="{Binding szEmpSerialNo}" /><DataGridTextColumn Header="Employee Name" Width="*" Binding="{Binding szEmpName}"/><DataGridTextColumn Header="Machine Code" Width="*" Binding="{Binding szEmpPunchID}"/></DataGrid.Columns></DataGrid>

I have used inotifypropertchnaged interface in object class for both datagrids

 public bool IsSelected
        {
            get { return bIsSelected; }
            set { bIsSelected = value; OnChanged("IsSelected"); }
        }
        public event PropertyChangedEventHandler PropertyChanged;
        private void OnChanged(string prop)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(prop));
        }

thanks in advance