is it possible to have one universal window for all tabs in vim? For example if I have a preview window open, that this window is the same for all the tabs, including its position and so on?
Short answer: not really.
Long answer: NERDTree fights against this and is far more complex for trying to do so.
From a comment:
The purpose of each tab is to allow for a different window layout.
In other words, I’ve seen people try to bolt this onto vim, and it’s kludgy, only half works, and frankly goes so against the grain of what vim tries to be that it becomes a sacrifice of productivity.
If you absolutely must, see if you can figure out how NERDTree makes it work. I’ll see about digging up the QA on vi.stackexchange.com.