I've spoken about PB here. Now my trial period there has ended, and I finally can see the FREE version of PB. That's not as simple as it might seem since you cannot download it anywhere or opt for it anywhere if I'm right, you just download the professional version which after 30 days goes crippled.
So this PB FREEWARE intrigues me, not for replacing anything, but as a kind of a useful toy.
And yes, you CAN export outlines from there, even with text... Yes, from the freeware version, even when in the file menu, all export commands are greyed out - no, I'm not doing something illegal, it's just knowing the software better than at first glance...

And yes, you can minimize the bottom box containing various functionalities, and yes, you can put the notes box on the left of the screen (= by default it's only a very large but squeezed-down field in the bottom box, necessiting endless scrolling if ever you dare doing more than one sentence or one and a half), allowing for ample writing (but beware, large texts there seem to get screwed up, see their forum); btw, F5 gives access to this notes box, but the real elegant thing is, when you just HOVER over any given node in your graph, containing text, this text will be shown in the box, without any need for pressing a key or something.
So you see, for playing around with some stuff, PB is really smart!
II
And this brings me to ActionOutline. Why? Because AO often drove me half-crazy when inadvertantly, I tried to cut and paste some text lines into the tree, instead of first making a new item and then pasting the textlines into the item; you must know that without any warning, AO then did as many new items as my text had textlines... and then I had the pleasure to select all those new "items", one by one, for deleting them, and with getting a warning to quit for every one of them!
III
And this brings me back to PB. As said before, you can export outlines, without or with text (= option), even from the free version; but in the same way, a lot of other programs can export outlines, PB is just a (good) example for a source program for outlines we'd like perhaps to import into MI.
As for PB, the outline is like this:
First item = root = no indentation
Then all items indented, according to their level, with multiple indentations,
every indentation being made by a tab, the root item being the only one without indentation.
If your outline contains text (= in the above-mentioned notes field, and option "with text" = "on"), this text is outlined the same way, so it's indistinguishable from outline items; for example:
Root item
Tab First-level-item
Tab Tab Second-level-item
Tab Tab Tab Text of second-level-item before
Tab Tab Tab Third-level-item
and so on...
Other programs might format such an exported outline in a slightly other way, but in any case, since we're speaking of text files, some manual or macro cosmetics could be applied before importing into MI.
IV
Thus, I tried some MI import formats; of course, the .Head format intrigued me, but to no avail: You can very well import such an outline into the tree of MI... and you seem to get nothing, except for the first item being in the tree. Then, when you go to any other item and back to the imported one - but then only, I tried several times -, you see your original (PB) outline (in my case) with the right indentation as text in your MI editor field.
This seems to indicate that whatever the .Head format was / is, it's not suited to import tab-indented text outlines...
Since, of course, when I want to import a text outline from any other program, I want the outline lines to become items in the tree (= like in AO), and whenever possible, correctly indented according to their tabs in front of them (= tabs which will get lost in the process, of course).
This would be the basic demand for importing such outlines; of course the big treat would be to have the possibility to do some other encoding character before text lines (manually, before importing that is), and that MI would then "know", this is not another item, but that's item text! (= the text of the item right before) - Perhaps such a goodie would be for another day...
V
At this time, if you just put your outline-to-be-imported into the clipboard, then select an item in your tree, then paste it (= control-v), you'll get the same result as above: First line as new item, and then the whole outline as text in the text field; btw, there seems to be a difference, one alternative gives the outline text without any indentation, the other shows the tabs - doesn't matter.
VI
Minor digression: This importing of a text into the tree, just the first line, then into the text field, is way, way more comfortable than the AO way, but UR - as often - does it one better: It does as MI does, but without replicating the first line, used for the item name, in the text field!!! Of course, that's much more logical: You've got a text, first line becomes the text's title = item's title, but only the rest of the text will be displayed in the text! (Remember, the item's title is, thankfully, already replicated ABOVE the text field, so we don't need it THREE times!)
VII
And now back again to AO since in this case (and only in this one), I would have liked MI to function as AO does: importing every line of text into a new item!
So why not doing exactly that, but with a warning beforehand?
So I tried, in MI, "Paste Special", but it was greyed out, no option there to import the text not in the usual way into the tree (like it is done with "Paste" = control-v, First line into the tree, all others into the text frame), but altogether into the tree, 1 line 1 item.
VIII
So this is the perfect solution:
a ) Make it possible, please, to just import as before, but suppress the first line then in the text frame
b ) Make it possible, please, to import, by an additional "Paste Special" option, any text in the clipboard not in the way a, but in putting it as a tree into the tree, first line being the "parent" of this subtree, and then, level indenting according to tabs before these lines = items
ad b ) Any text there will thus become an "item" which is not wanted, but this manual correction afterwards will be inavoidable; most users will probably just want to import naked outlines, without those additional texts.
IX
Speaking of PB, one of their most elegant features is their search... in their forum! Since you can opt for display of the search results as threads, or as posts. This doesn't seem to be spectacular, but in fact it is:
Let's say you have 20 search results. Then that optional display mode presents a NEW thread, containing all those 20 hit posts, be them from 20, 10 or 1 original threads, and from each such post in this new thread, you can then of course, in your browser, by special click, open that particular original thread in a new tab.
This is the most elegant search result feature I've seen to date, so have a look at it, it's state of the art, really.