Timebar selection changed issue

[Yesu]

Hi,
when i move the slider from one month to another month in timebar it showing next month first day record in the grid view.How can i solve this issue.
please give me advice
This is the order which i gave in code behind
 InvoiceTimeBar.PeriodStart = new DateTime(2009, 1, 1);
            InvoiceTimeBar.PeriodEnd = new DateTime(2013, 4, 30);
            InvoiceTimeBar.VisiblePeriodStart = new DateTime(2012, 1, 1);
            InvoiceTimeBar.VisiblePeriodEnd = new DateTime(2012, 12, 31);
            InvoiceTimeBar.SelectionStart = new DateTime(2012, 1, 1);
            InvoiceTimeBar.SelectionEnd = new DateTime(2012, 12, 31);