How can I check to see if a valueChanged event of a Swing JList was changed via click or mouse?

Question

Here's some example code, using Groovy's swingbuilder to create the code for the valueChanged event of a JList:

    mainList.valueChanged = { event ->
        if (event.isAdjusting) {
            index = mainList.selectedIndex
            otherList.clearSelection()
            otherIndex = otherList.selectedIndex
        } else {
            mainListSelected = true
            clearJList(otherList)
        }
    }

I have two JList's, and this function kind of controls which list is allowed to be selected via the mainListSelected variable. We also then have to change int eindex we want to use from the selection based on whether or not it's an index from mainList or otherList

I've read about event.isAdjusting, and it only fires twice like this on a mouse click event. With this knowledge, you would think I would just move everything out of there, but I need certain things to happen differently if the mouse is what causes the event as opposed to using arrows. However, with this code, using arrow key navigation prevents the index from ever changing.