First of all let me congratulate you on the great product.
I need to display text generated in RequestCellToolTipText event in columns. How to do it?
Is it possible to change at runtime a tooltip font to another, in this case monospaced font?
Regards,
Piotr Pikielny

It seems, this is an incomplete description of your task. Can you give us a more detailed description accompanied with a screenshot? Do you need to display cell tooltips on demand? If you define it in the RequestCellToolTipText event, it is displayed in the cells - but only when the user places the cursor into the cell and doesn't move it for some time.

The tooltip font can't be changed using the public properties of iGrid. iGrid's built-in tooltips are implemented using the standard System.Windows.Forms.ToolTip class, and hence they are drawn by the OS using the default tooltip system font. However, you have the iGrid source code and can implement custom drawing for tooltips yourself:

ToolTip.Draw Event
https://msdn.microsoft.com/en-us/library/system.windows.forms.tooltip.draw(v=vs.100).aspx 

Sure, this will require some work from your side, and you should decide whether the result is worth the effort.

Yes, I need to display cell tooltips on demand. I defined it in the RequestCellToolTipText event. As you said, tooltip is to be displayed in the cells but only when the user places the cursor into the cell and doesn't move it for some time.
A cell tooltip text needs to be presented in three columns, e.g.
Make Plan AA 2
Assess Risk BC 5
etc.

The WinForms ToolTip component does not allow you to do this. Only one tooltip window can be displayed at a time, and only when the mouse pointer isn't moved for some time.

Do you want to say that you may have 2 or 3 tooltip windows displayed simultaneously? I hardly understand this. Can you show us a picture of what you need? Perhaps, we can tell you another solution how to implement this functionality in iGrid.

That's my fault I haven't made myself clear enough from the very beginning. Sorry for that.

In 'RequestCellToolTipText' event, when the user places the cursor into the cell and doesn't move it for some time, the multiline text similar to 'displayText' in the example below is generated and displayed.

void iGrid1_RequestCellToolTipText(object sender, iGRequestCellToolTipTextEventArgs e)
{
string displayText = "Make Plan" + "\t" + "AA" + "\t" + "2" + "\n" +
"Asses Risk" + "\t" + "BB" + "\t" + "3" + "\n" +
"Delete Folder" + "\t" + "CC" + "\t" + "4";
e.Text = displayText;
}

'displayText' may have several rows. Each row consists of three pieces of information separated by tabs. In first column, there are names of different length. To make it simple, in the example above I put one "\t" after each name. The issue of inserting an adequate number of tabs after first column of each row is solved. Symbols in second column are short so one "\t" is always enough.
It all works fine but sometimes - because font is not monospaced - the display in columns is not preserved which obviously doesn't look nice. That's my problem. Normally, the solution is to use monospaced font. That's the reason I asked you how to change font used in tooltip. I understand it is not possible to do it in iGrid. Do you have any ideas how to solve this problem?

I think you need to use the CellMouseEnter event and display your own tooltip window from it. It can be the same WinForms ToolTip control or another special mini-window with the required formatting (a monospace font, color, etc.)

You will also need to suppress the default iGrid cell tooltip. Set e.Text to an empty string or null in the RequestCellToolTipText event for that.