My bad. I should not have called it a Windows issue. Properly I should have said that it was apparently neither a Dreamweaver nor a WebAssist issue. I may very well stay with Windows 10. The image I have contained Dreamweaver CC 2015. I am doing all the updates so it will be a CC 2017 when done. My windows Seven system on that machine was getting flaky anyway. I will update this as soon as I can.
Update: It is working properly in Windows 10. It is now clear that it was not a problem with either Dreamweaver or WebAssist. What the hell, I guess I will stay with Windows 10 now.