sorry didnt understand, the location, size, and any other options are defined by the user in the user setting so of course it retain the user preferences!
even after saving and quitting the session the location of thoses open floaters will stay the same.
The only ‘Problem’ is that ( i think ), i will have huge troubles making floaters from precedent session always on top automatically each new session, remembering thoses who were open is not the problem tho.
Update ADDON
the custom camera floater is ready, and have a lot of options !
if the active object is a camera, the camera will automatically be set to this camera.
i also activated an option for no hud, another for no header, another for set up automatically the to rendered view, another to lock the camera to the view
this is an example, of one of the many, many custom floater i can create… if this addon sell well (i hope), i will support a lot of customization and special floaters like this one.
edit
also made it work for lightning !
Ah, should’ve been clearer. I meant remembering last size/location of custom floaters after closing.
For instance, if I load up the Outliner, position it somewhere and resize, accidentally close it, and I load up the Outliner again (in the same scene), I would want it to open up at the location and same size as last time. Small convenience, but it could be annoying to have these custom floating windows reset every time.
Of course, I’d be okay with it resetting on a new scene.
Maybe there could there be an option for the custom floating windows be dynamic in what it remembers for size/location after first launch (per Blender scene)? To me, that would be the more ideal behavior.
Best of luck in figuring that out! 
Conveniences like that I would consider quite fundamental for an add-on like this.
There’s no way to do that, i cannot retain the last configuration of a floater when the user close it.
right now i agree, it’s annoying because there’s not a lot of customization avaible for your floaters, but it will happend soon, so you’ll just have to configure the default look of your future floater and your’e good to go.
For example in the 3D view floater will have options like hide header, hide toolbar, hide prop bar, change overlay, change viewsetting, auto-isolate selection, auto set to top, ortho… ect…
not really, you just have to spend an extra 10 seconds setting all your floaters to a floating state manually on each new file opening with floaters in it.
Super geeked about this add-on! Great work!
So I am not sure when the post title was edited, so it says “tomorrow”? haha. Do you have an exact date? (06/14/19 or 06/15/19)?
2019-06-15T10:00:00Z Saturday at noon, for europe central.
*edit : sorry its going to be later in the week, blender market need to do a review first ! i don’t know the possible date then.
Thanks! Looking forward to it!
Great progress!
Another idea: Any possibility to implement User defined (Loc, Size…) preset dependent on workspace?
for the first realease, each windows are going to be workspace dependent because of how blender handle weirdly new windows…
see below
more on that to come on the future manual
but i will create floating workspace in the future, and switching between them will be fast
It’s a shame there isn’t an easy solution to this. I guess we’re just going to have to wait until the official implementation of floating windows into Blender (which may still unexpectedly suddenly happen, like the left-click as default project).
Anyhow, looking forward to seeing how your add-on turns out!
oops, blender market don’t allow me to publish directly 
they need to review it first
that give me a large ammount of time to write the manual then.
that give me a large ammount of time to write the manual then.
If this can help you… 
Tabs/windows for Add-ons (N-panel) floating too? I think it’s would be very powerful. 
Like this for example (in 21:9):
This is a mock up right ?
i could do it but i will need to draw a 3dview with nothing in it for every N panel the user want floating, is really it worth it ? most users will have a fully open 3d view taking a large part of their screen anyway, so the n panel will be easely accessible.
so yes i can do something like that, but the size of the windows will not adjust automatically
I thinks this would be a very useful option for ultrawide monitor’s users. 
i made this addon because i wanted to “free” the inteface from unused spaces. you pop up a floater when you need it, and when you don’t you just close the window. No headache of re dividing everything… changing the whole interface again… ect…
i don’t really think that using my addon for keeping a lots of menus always open is that of a great idea ? is it ? it feel kind of a waste of spaces.
when im seing this image i really wonder if you really make a good usage of your screen , keeping all thoses menus open.
it’s just an advice, it will be possible to do that within my script anyway even if im for or against it, just for the sake of freedom.
" i don’t really think that using my addon for keeping a lots of menus always open is that of a great idea ? "
But someone might use it for that.
" it feel kind of a waste of spaces "
" Large 3D View ( without properties… )
Useful Add-ons and tools on the right and left side.
Work would be faster I think ( “all” in one screen with large 3D view ) "
So… I think (!) this is not waste of spaces.
No offense… it was just an idea for an option. 
If we can put any floating windows on second monitor than i will buy it since who in his right mind would work only on a single monitor!
No i don’t criticise this is just my idea of the whole thing , do what you want with this addon it is made for that ! freedom ! and yes your idea is great i will try to pull this out
@polynut you can put any windows were you want. the only limitation, for now, is workspace change.
found a way to customize the name of a window. not ready to be implemented at all tho.
import bpy
import ctypes
from ctypes import *
title = "MY CUSTOM WINDOW NAME"
b_string1 = title.encode('utf-8')
Active_W = ctypes.windll.user32.GetActiveWindow()
ctypes.windll.user32.SetWindowTextA(Active_W,ctypes.c_char_p(b_string1)) #rename window not working
im currently trying to figure out how to customize the look of a window.
so we could have some decent custom software dedicated windows like any other software do, and maybe with, who knows, a little pin icon.
that is way out of my leagues but im trying anyway.