>Hi everyone!
>Here is a such a strange thing...
>If you have a timer on your form and call another form from first one, form which has a combo box, combo box does not work properly.
>Item in combo box can not be choosen as it's you wish.
>When you got rid from timer everything is fine. But I really need a timer. All I could do is create my own combo by crossing textbox, pushbutton and popup menu which is very stupid. May be you have more wise solution.

There is MS reported problem here. I guess you could search in MS KB, but also you could try to stop timer in Combo.Gotfocus or better DropDown event and restart it from Lostfocus event.