Prevent bringing child windows to top, how?

Hi all, I have an .Net Windows form application that creates two other forms. when I click on the main window, the child forms stay behind other [apps'] windows; this is okay. However, when I click on one of the child forms, the second one also brought to the top, which covers other applications' windows. How can I prevent this? that is I don't want my app to show other child windows except the one that is been clicked on. Thanks for any suggestions, - JB

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