C# tooltip doesn't display long enough

Set the AutoPopDelay property to be something higher - it defaults to 5000 (5 seconds)

Update: My mistake:

The maximum time you can delay a popup is 5000 milliseconds. For longer durations, use the Show method to control the exact moment when the ToolTip is displayed.

So you can't get the tool tip to be displayed for longer than 5 seconds using this method - instead you need to use the Show to explicitly show the tool tip when the user hovers over the picturebox. Just replace your call to SetToolTip with one to Show in your MouseHover event handler:

ToolTip tt = new ToolTip();
protected virtual void pictureBox_MouseHover(object sender, EventArgs e)
{
    tt.Show("Click 'LIVE ...", this.pictureBox, 10000);
}

Set the value of AutoPopDelay property

 tt.AutoPopDelay = 10000;

Unlike the answer described by Justin, I was not able to get the ToolTip to display for longer than the 5 seconds using the show method.

One of the other hangups I was having was the AutomaticDelay property. Long story short - if you want custom AutoPopDelay do not set AutomaticDelay.

Setting this property will automatically set... see MSDN:

AutoPopDelay = 10 x AutomaticDelay

InitialDelay = AutomaticDelay

ReshowDelay = (0.2) x AutomaticDelay

Here's code that worked for me:

ToolTip tt = new ToolTip();
private void someObjectName_MouseHover(object sender, EventArgs e) {
    tt = new ToolTip
    {
        AutoPopDelay = 15000,  // Warning! MSDN states this is Int32, but anything over 32767 will fail.
        ShowAlways = true,
        ToolTipTitle = "Symbolic Name",
        InitialDelay = 200,
        ReshowDelay = 200,
        UseAnimation = true
    };
    tt.SetToolTip(this.someObjectName, "This is a long message");
}

Bonus:

private void someObjectName_MouseLeave(object sender, EventArgs e)
    {
        tt.Active = false;
    }