Bring the orange juice and zest, lemon juice and zest, and brown sugar to a boil in a saucepan over medium-high heat. Reduce the heat to medium-low, and simmer until slightly thickened (about 5 minutes). Remove the dressing from the heat and stir in the vanilla extract and poppyseeds. Set aside to cool completely.
Remove the stems from strawberries and chop into large chunks. Add to the bowl.
Thoroughly drain the mandarin oranges, remove the stems and thinly slice the strawberries, and peel the kiwis, halve them, and then thinly slice them. Remove the grapes from the stems.
In a large bowl, add in the prepared mandarin oranges, sliced strawberries, sliced kiwis, grapes, blueberries, mangoes, blackberries, and raspberries.
Pour the dressing over the salad and lightly toss the ingredients together.
Return to the fridge to allow to cool and let the flavors meld.
Serve after the salad has been chilled, tossing once more.