I developed a program in 'c' that has worked in all versions of Windows prior to Window 10. When running in Windows 10 when I create a dialog box, I get two boxes, one covering the other. The top box works properly and can be closed. But then the second box comes to the top and doesn't respond to any input. This lock up the program. The stranger thing is that I don't get this problem on my second computer which runs Windows 10 that was upgraded from Windows 7.