private void clearListeners(IPlottingSystem plotSystem, IRegionListener listener) {
if (plotSystem == null) return;
Collection<IRegion> regions = plotSystem.getRegions();
if (regions != null && regions.size() > 0) {
Iterator<IRegion> it = regions.iterator();
while (it.hasNext()) {
IRegion region = it.next();
region.removeROIListener(this);
}
}
plotSystem.removeRegionListener(listener);
}
