Hi there! I am a hardcore KDE, okular user... My ram usage at the current time I am writing is total:16GB/ used:13GB/ free:3GB. I have currently 65 open pdf files with okular (no, I don't want to close any of them), and I save the session when the computer restarts, so Kwin replaces the windows in the same activity,desktop and position as before. Currently okular uses 5.5GB. I like one feature that programs like libreoffice, calligra and kate have, which is to open a new window for a specific instance of a document. What I currently do is open the document in a second instance, which has the flow that okular uses additional ram for the same document , and pages load as slowly as if they load for the first time.
In libreoffice you can use Window→New_Window
In kate you can use View→New_Window
In calligra View→New_View
Is such a feature easy to implement? Unfortunately, I am not a developer, so I would like to post it as an idea... Am I posting in the right place?

While it would be simple for Okular to launch another instance of itself, reading the same document, I suspect it would not be simple for them to share the memory representation of the document. This is because Okular uses a separate process for each document viewed, while other applications such as Libreoffice use a single process for all documents (which is more vulnerable to data loss if a crash takes place).

I'm not sure which approach Calligra uses - if it uses separate processes then I suspect it likely re-renders the document as well.

I can confirm that Calligra does not re-render the document.
You can try Calligra like this
run calligrawords→View→New_View
Check out that there is one process for the same document
then run calligrawords again to open a new file, and you can notice that there are two processes now...
Now open more views for a single document and notice that there are a single process for as many views as you like.
I can confirm that the same happens with Kate→View→New_Window

I think this is a really nice feature, this is a screenshot of a single desktop with 3 instances of the same pdf file. I use the tabbing-grouping feature of Kwin.
http://postimg.org/image/svk3ft1il/

I see. In this case i'd advise filing a feature request at bugs.kde.org, although the developers may still decide to not implement this feature.

bcooksley wrote:I see. In this case i'd advise filing a feature request at bugs.kde.org, although the developers may still decide to not implement this feature.

This is not exactly easy, and there is already a wishlist/feature open (it's possible to vote for it, but again it depends on the (shortage of) available manpower):
https://bugs.kde.org/show_bug.cgi?id=169847