No, you can't open 2 Editors at the same time.
First you have to mark one option: File > Perferences > General > Automaticlly create unknown variables.
Now you open the spellpack map, select one trigger and press cntr + c to copy it. Now you open your map in the same editor without closing it and press in the trigger section cntr + v > so you copy and past it by hand.
Well you can import and export the whole trigger section, but since in most spellpacks are many "this-map-only-trigger" and then you have to delete them and possible it wast more time then c&p
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