Thanks to the this link, this issue is fixed. Go read his site for a better answer than mine, but, in case his site ever goes away, here are the relevant snippets:
Notepad2 windows are now assigned to a custom
AppUserModelID
, that's why multiple icons may appear if Notepad2.exe is directly pinned to the taskbar. To fix this, open a Notepad2 window first, and then pin it to the taskbar from the Notepad2 taskbar button context menu.
Note that if you have followed the rest of his instructions on the page and set it up to redirect notepad.exe
to notepad2.exe
, you actually have to start up Notepad2.exe
directly, then right click on the taskbar instance and click "Pin to Taskbar".
Now that I did that, all my Notepad2 instances stack in the same place on the taskbar!
Note that the author of Notepad2 says that you have to add code in your application to handle this.