SORRY AGAIN, AMPA, see above.
rjbull and tomos,thank you both very much for your kind hints.
In fact, I also tried these, and if I may give an advice here (while hoping for somebody else having something better to "offer"), these "scrap containers" by xplorer2 are the best solution so far: They are independent windows that can be placed "always on top" if needed, sized down to rather tiny sizes, and thus can be shown, too, when the xplorer2 window is minimized = hidden. The content (the link list) is saved into a file, and you can load these special files into these containers, which means, instead of having many such little panes cluttering your screen, you should have one such pane, and switch these special list display files (".cida" files) there, by macro: A little menu with 20 cida files, to be loaded into a single container. I just made up this idea in this moment - seems to be, by far, the best way to do it today, since it avoids the necessity to switch between a file manager and your main programs, a text editor and your main programs, or an outliner and your main programs.
tomos, you say, "I use an outliner myself with linked files - with mixed success." Oh yeah! The problem here is that either you switch between the outliner tree (with its links) and your main program, or even when the outliner is your main program, any link triggered will hide your current project tree, with those links, and you have to switch again, back and forth: your project is not in continuous visibility.
That's why I've being searching for "better", without finding something, except, now, this ".cida" file switching in a narrow pane, which means your main application will NOT be displayed in a maximized window anymore - and, as said in the other thread, there's no manual rearranging of entries, except for deleting them and then reimporting your links, one by one, in a certain order, and with the setting "no automatic sorting": not good! but such links are managable if your list doesn't get too long. Other problem, you cannot bold or color your links in such a pane, for example for reminding what's needed today, what's needed tomorrow, etc., or for doing subgroups, by colors - all this is possible with the links within an outliner tree, let alone the manual rearrangement which is without problem there! And the developer of xplorer2 is not responsive, doesn't even see what he's got there, so a little bit tweaking might be so helpful for his business.
Years ago, there was "Virtual Folder", then renamed to "Virtual Disk". See both sites, virtualfolder.net and virtualdisk.net. From their graphic appearance, you would think these sites are well and alive, modern, working. When in fact both sites have been out of business for four years now. Try their "buy" buttons, and you'll see what I mean, and that's been persistent since 2009!
So, a tiny little application did exist, but before my becoming aware of it, and today, it's really xplorer2 the only possibility to have such a list at hand, here depending on a full file manager, but without that being visible - perhaps with DO, it's similar, that you can hide the main window, but just display one such "lister", so that would make it two.
For any other possibility, you must display the main program, the editor, the outliner...
And then, there is tagging programs, of course, some even with tiny windows. Tagging, by the way, does not let you manually rearrange items, either (that's another advantages of trees over tagging: not the (wanted) subordination effect (levels), but also, just ordering items of equal indentation level) - tagging does not do this, but produces unordered (or then, alphabetically "ordered" / in fact alphabetically mixed up item lists).
As for Virtual Folder / Virtual Disk, I suppose they would not offer such (persistent) manual rearranging either (and lately, I checked Speed Commander for this, too: it doesn't do it, and then, you'd have the whole big Speed Commander window in front of you, instead of your respective main application).
I'll let pass Listary an nth time: The "back to previous" functionality can be replicated by macros (storing variables), the "find as you type" functionality seems to be better implemented in QuickJump (didn't DonL say his XYplorer will have this functionality soon, in some post some months ago?) (and Listary's example for "fuzzy search" is horrible, would bring thousands of false hits in real life) - and yes, rjbull, you're right, I complain because Listary isn't a project manager "in the sense that I want it to be", or let's be frank, it's not a project manager at all; Tabbles is terrible, by the way, another complaint of mine: Yes, they make promises that in real life don't hold.
But then, I do many macros, and prefer working on them in order to better integrate those tasks into my workflow, than an additional tool could do. But for people not working so hard on macros (which is time-consuming and often frustrating), a ready-made solution like Listary is of course worth easily 20 dollars, let alone 10, no way out here. (Will finally trial QuickJump, by the way, and report if it lives to the expectations it rises.)
P.S. In fact, it's incredible that in 2013, there is not a single file manager, not a single extra tool, that allows for putting links in a list, AND allows for shifting entries around, for formatting them (bold, italics, underline), and for coloring them. BUT I just think that I didn't try 1-pane outliners for this, so far, or a 2-pane outliner where you would hide the text field, by pushing it beyond the right border of your screen. And I tried ListPro for this (last week on bits), with not much success, but should try again (my criteria were different at the time). But what a fuss! And this makes me remember the existence of "To-Do" tools, just little list things, the more minimalistic the better: They are written to help you in prioritizing and grouping, so it's here that the solution to this problem will probably lie - it seems I was too much focussed on file "managers" of all sorts, when in fact, "To-Do managers" will probably have on offer much more acceptable solutions!
So much for Listary on my side, but "projects", well, Listary does not. ;-)