docs: private void updateHighlighting(boolean initial) {
  
          Map<I_CmsDropContainer, CmsPositionBean> containers = new HashMap<I_CmsDropContainer, CmsPositionBean>();
          for (I_CmsDropTarget target : m_dragInfos.keySet()) {
              if ((target instanceof I_CmsDropContainer)
                  && !Display.NONE.getCssName().equalsIgnoreCase(
                      CmsDomUtil.getCurrentStyle(target.getElement(), CmsDomUtil.Style.display))) {
                  if (initial && (target != m_initialDropTarget)) {
                      ((I_CmsDropContainer)target).highlightContainer();
                  } else {
                      ((I_CmsDropContainer)target).updatePositionInfo();
                  }
                  containers.put((I_CmsDropContainer)target, ((I_CmsDropContainer)target).getPositionInfo());
              }
          }
          List<I_CmsDropContainer> containersToMatch = new ArrayList<I_CmsDropContainer>(containers.keySet());
          for (I_CmsDropContainer contA : containers.keySet()) {
              containersToMatch.remove(contA);
              for (I_CmsDropContainer contB : containersToMatch) {
                  CmsPositionBean posA = containers.get(contA);
                  CmsPositionBean posB = containers.get(contB);
                  if (CmsPositionBean.checkCollision(posA, posB, HIGHLIGHTING_OFFSET * 3)) {
                      if (contA.hasDnDChildren() && contA.getDnDChildren().contains(contB)) {
                          if (!posA.isInside(posB, HIGHLIGHTING_OFFSET)) {
                              // the nested container is not completely inside the other
                              // increase the size of the outer container
                              posA.ensureSurrounds(posB, HIGHLIGHTING_OFFSET);
                          }
                      } else if (contB.hasDnDChildren() && contB.getDnDChildren().contains(contA)) {
                          if (!posB.isInside(posA, HIGHLIGHTING_OFFSET)) {
                              // the nested container is not completely inside the other
                              // increase the size of the outer container
                              posB.ensureSurrounds(posA, HIGHLIGHTING_OFFSET);
                          }
                      } else {
                          CmsPositionBean.avoidCollision(posA, posB, HIGHLIGHTING_OFFSET * 3);
                      }
                  }
              }
          }
  
          for (Entry<I_CmsDropContainer, CmsPositionBean> containerEntry : containers.entrySet()) {
              containerEntry.getKey().refreshHighlighting(containerEntry.getValue());
          }
      }