Cap activeIndex's minimum to -1.

Author: JeromeLam

src/select.js

@@ -551,7 +551,7 @@
           break;
         case KEY.UP:
           if (!ctrl.open && ctrl.multiple) ctrl.activate(false, true); //In case its the search input in 'multiple' mode
-          else if (ctrl.activeIndex > 0 || (ctrl.search.length === 0 && ctrl.tagging.isActivated)) { ctrl.activeIndex--; }
+          else if (ctrl.activeIndex > 0 || (ctrl.search.length === 0 && ctrl.tagging.isActivated && ctrl.activeIndex > -1)) { ctrl.activeIndex--; }
           break;
         case KEY.TAB:
           if (!ctrl.multiple || ctrl.open) ctrl.select(ctrl.items[ctrl.activeIndex], true);