So i found the solution
The bug was in
this.scheduleControl1.ScheduleType = ScheduleViewType.Month;
if u set the Visual Style without setting SheduleType nothing will changes
As experiment i open ur ScheduleSample and comment this code
//this.scheduleControl1.ScheduleType = ScheduleViewType.Month; - after it no Visual Styles !!!
Working code :
InitializeComponent();
this.scheduleControl1.ScheduleType = Syncfusion.Windows.Forms.Schedule.ScheduleViewType.Month;
this.scheduleControl1.Appearance.VisualStyle = Syncfusion.Windows.Forms.GridVisualStyles.Metro;
Not Working Code
InitializeComponent();
this.scheduleControl1.ScheduleType = //Syncfusion.Windows.Forms.Schedule.ScheduleViewType.Month;
// this.scheduleControl1.Appearance.VisualStyle = Syncfusion.Windows.Forms.GridVisualStyles.Metro;
Fix this !!!!