Ok I'll have a crack at it
I also noticed that when widgets are imported into DesktopX, the DesktopX popup menu on the taskbar icon switches to a widget menu and no longer controls the main DesktopX screen.
If you are using the DesktopX "Import" function to load widgets (the .exe files), try just running them either by double-clicking on the .exe file or using a shortcut to it, just like you would any other .exe file. Sometimes the widget contains menu scripts which will do what you're describing if the widget is Imported. Also I've run into some clock widgets which just don't seem to work right period if they are Imported. The problems disappear when the widget is run instead; generally speaking it's better to run the widgets with a double-click or shortcut unless you're wanting to modify them within DesktopX.
Has anyone had the problem with widgets and objects placement on the screen switch to 0,0 when a new window is opened?
Not quite sure what you mean here, xy position 0,0 as in top left corner of the screen? No, I haven't run into that. Could also be caused by Importing a widget I suppose, hard to tell. Maybe the running vs. Importing will take care of that too. If not, it might be a monitor management utility getting in the way like UltraMon (?) or Nvidia's or ATI's utilities - I have forgotten the names, but I'm talking about the utilities that let you control how windows are placed when programs are opened.
I'm also wondering if you're talking about individual widgets (.exe files) and objects (.dxpack files) or complete desktops (.dxtheme and .desktop files). I don't run the desktops, but I run the widgets and objects without any real problems on dual monitors and I know other people do too, so it's something you can most likely fix.
Any of this help?