invert boolean operation for readability and add comment

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/components/views/dialogs/AddressPickerDialog.js

@@ -523,8 +523,9 @@ module.exports = React.createClass({
             selectedAddresses[addressType].add(address);
         });
 
+        // Filter out any addresses in the above already selected addresses (matching both type and address)
         const filteredSuggestedList = this.state.suggestedList.filter(({address, addressType}) => {
-            return !selectedAddresses[addressType] || !selectedAddresses[addressType].has(address);
+            return !(selectedAddresses[addressType] && selectedAddresses[addressType].has(address));
         });
 
         const query = [];