I run the evaluation version of UE v11.10a+1. Up to now I like very much, but there is one thing that bugs me a lot.

I like to work parallel on many text-files open in one UE instance. After closing UE and restarting it from the desktop I see all the files I had in my last session reopend - that's what I expect.
However, if I START UE by double clicking on a txt file in the file browser, that particular txt file is opened in UE and all other files (that where open in my last UE session) are closed. Then I can only reopen them from the file menu one after the other again.

Any idea how to start UE by double clicking on a file without loosing my old open files?

There is an option in 'Advanced>Configuration...>General>Load/Save/File Handling Options' called 'Reload files previously open'.

Have you tried using this?

yes I tried this, and it won't work.

Only way I know of is to set your file associations to use a different .ini. Then you'll end up with once instance of UE when you double click or use the right click menu and another instance when you open UE directly. Not ideal for your situation, but I believe UE is working as designed.

Working with different ini-files is a bit too sophisticated for me (for the time being), but thanks nevertheless!

In the meantime I found a workaround:
I created a project file dummy.prj, which includes SOME txt-files I worked with recently. When I START UE by double click on a text file from the file browser, then all my old files, which were open when I closed UE the last time, are still gone. BUT by opening that dummy.prj file ALL txt-files, which were open when I closed UE the last time, will be opend again. As I said ALL txt-files, not only the SOME text-files, that are included in the dummy.prj.