can't use word and preview on the same screen

[iNeedToDoHw]

So lets say i have 1 word window open at a full screen and on top of that, i have preview on the left half and word on the right half. So I am currently seeing word on the right and preview on the left because i need to copy some information down from a pdf. I don't know why, but when I click on word, both word windows come up and the pdf preview windows goes behind the full screen word window.
How can I have preview window and word window at the same time while having a full screen word open in the back?

 

[MisterMe]

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How can I have preview window and word window at the same time while having a full screen word open in the back?

I am afraid that you don't understand the concept of fullscreen. Fullscreen means that only one application occupies the whole screen. All other running tasks are consigned to the background and cannot be seen.

 

[iNeedToDoHw]

sorry, full screen as in "larger window" not actually full screen that you have to swipe the touchpad to get to...