Turns out that it was implemented in one of the Windows 10 updates. See the following blog post, search for "run":

https://blogs.windows.com/windowsexperience/2017/09/13/announcing-windows-10-insider-preview-build-16362-pc-skip-ahead/

Try holding Ctrl and Shift. See:

https://www.winhelponline.com/blog/run-command-elevated-administrator-ctrl-shift-enter-windows-10/amp/

Please see:

https://tweaker.userecho.com/communities/1/topics/469-add-option-to-disable-minimize-window-when-clicking-already-active-window

Please see my reply here:

https://rammichael.com/7-taskbar-tweaker/comment-page-17#comment-3660

The order of taskbar thumbnails, if that's what you mean, is not remembered by the tweaker. While 7+ Taskbar Tweaker allows to reorder the thumbnails, it cannot restore that order when Firefox restarts, since the thumbnails are not identifiable in any way. That's something that needs to be handled by Firefox itself in order to work properly and be persistent between different launches of the program.

I'm not familiar with RemoteApp. The feature you're asking for requires investigation that I'm unlikely to do, sorry. I also believe that it's less related to the tweaker, since it's not about tweaking the taskbar, but about making it run/appear in a specific situation.

Perhaps asking in a forum such as superuser.com will yield some results.

About the source code of 7+ Taskbar Tweaker, it's not available, but again, I don't think that it can be helpful in this case.

Does it work when you run it manually? If it does, it's clearly a system issue which is unrelated to the tweaker.

Which version of 7+ Taskbar Tweaker are you using?

What is your Windows build number?

You're either using an old version of the tweaker, or an insider Windows 10 build.

Which version of 7+ Taskbar Tweaker are you using?

Also, please post the exact text of the error message, including the error code number.