winforms - tooltip of statusbar labels not showing up

I have a couple of labels in status bar, on which I have set tooltip.

statusLblWeek.Text = weeklyHrs.ToString();
statusLblWeek.ToolTipText = " Consumption of t开发者_高级运维his week " + statusLblWeek.Text;

Status labels are displayed correctly but the tooltip is not showing up. Why?

Use property StatusStrip.ShowItemToolTips

True if ToolTips are shown for the StatusStrip; otherwise, false. The default is false.

statusStrip1.ShowItemToolTips = true;
statusLblWeek.Text = weeklyHrs.ToString();
statusLblWeek.ToolTipText = " Consumption of this week " + statusLblWeek.Text;