Hi I have a Windows Form application. I have a Textbox. I want to implement a functionality like when the user clicks on the textbox, a list should be made available to the user and then the item selected from the list should be filled in the textbox. The list should not be available if some other control is focussed other than the textbox. What would be the better way to do this? Should I implement the list in the same form as the textbox or should I use another form for the list?

I want to implement a functionality like in the Tally Accounting Software.