same file in different split windows

The commands [Split Horizontally] and [Split Vertically] should do what you want if I understand the question correctly. You can find the keybindings for them using [Find Action...] which is typically bound to Ctrl-Alt-A.

Yes, that kinda does what I want but I already knew that.
The problem is it just works once if I only want to have a double split view.

Say I have 6 files open in one window, I select one file and choose split-vertically
and I get for that single file what I want. Now let's say I want 2 more files in BOTH views,
how(/if?) can I do that? Even splitting again and then dragging the newly created view to the other
pain doesn't work (it auto merges to the already existing one :( )

I found: http://stackoverflow.com/questions/1846565/how-to-create-two-editor-windows-for-the-same-file
and http://youtrack.jetbrains.net/issue/IDEA-34593
but the threads are somewhat confusing.. looks like it did work in earlier versions and
the 'bug' is now on "won't fix" status.

Thanks!

Let's assume you already have 2 tab groups: 1st have file1, file2 & file3 and 2nd group have file2.

Now you want to have file3 to be in both groups. There is no direct action to do this in one click/key-press -- but here is some two-step solution:
1) split the desired tab -- now you have 3 groups
2) drag newly created tab (from 3rd group) to a desired group (in our example it is 2nd group) -- now you have 2 groups only.

Even splitting again and then dragging the newly created view to the other pain doesn't work (it auto merges to the already existing one :( )

Worked fine for me in PhpStorm. Unfortunately I do not have IntelliJ IDEA on my current PC to verify that ATM.

Ha.. I seriously tried that a couple of times before (as I mentioned it earlier).
But I was just doing it 'wrong'. I dragged the tab to the other tabs and then it
looked like it merges to the old group.
But if I drag it right into the window/editor it works. stupid me ;)
thanks :)