Tooltips stops working


I have the following code:

            gpi.toolTip.InitialDelay = 500;
            gpi.toolTip.ReshowDelay = 100;
            gpi.toolTip.AutoPopDelay = 15000;
            gpi.toolTip.ShowAlways = true;
            gpi.toolTip.UseAnimation = true;
            gpi.toolTip.UseFading = true;
            gpi.toolTip.Active = true;
            gpi.toolTip.Tag = gpi;
            gpi.toolTip.Popup += new PopupEventHandler(toolTip_Popup);

            gpi.toolTip.SetToolTip(gpi.label, "NA");

        private void toolTip_Popup(object sender, PopupEventArgs e)
            if (bSetTooltipOnce) return;

            ToolTip tt = sender as ToolTip;
            GraphPaneItem gpi = tt.Tag as GraphPaneItem;

< here build the string to show at the tooltip >

                bSetTooltipOnce = true;
                tt.SetToolTip(e.AssociatedControl, text);
                bSetTooltipOnce = false;

The problem is that the tooltips works several times, but then stops working. A control which showed tooltips for one time or two, will stop showing it on the next attemps.

Why is that? How can I make the tooltip work always?

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That also happens in Windows System Tray area..
Try to hover mouse above the clock and let the tooltip show.
Don't move the mouse until the tooltip dissapear.
Move the mouse around, and try to hover it above the clock again.
Nothing happens?

That's the scenario at my machine, which is, sadly, up to date with
Windows' updates...

If that's the same with you, then.. Oh well.. :) Let's just wait until
it becomes an official bug in the Windows Bug List, and let us pray
it will be solved quickly :)

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