I have a shortcut to start my screen saver on my taskbar. Since it runs using explorer.exe, any time I open a new Explorer window, the buttons get grouped onto that item. I believe this as a bug because the default Windows taskbar buttons do not behave this way.

The screenshot shows my primary and second monitors, each with a handful of Explorer windows open. You can see that the buttons all collapse onto the screen saver button on the DisplayFusion taskbar. However, the primary Windows taskbar behaves as expected.

I suspect this is because DisplayFusion is only looking at the path for an item to determine whether it should be grouped. In my case, the screen saver shortcut passes a command line parameter to explorer.exe. The button for a new Explorer window has no command line parameters.

Sure thing. Here's my whole setup. In case the image doesn't load, the relevant portions are:

Windows Explorer (regular entry)
Path: C:\Windows\explorer.exe
Command Line: none

Screen Saver:
Path: C:\Windows\explorer.exe
Command Line: "C:\Program Files (x86)\DisplayFusion\DFSSaver.scr"

Hope that helps.