Program: 75014
Project: 75014
Buggy source:
/** 
 * Invalidate the presentation of the positions based on the given added positions and the existing deleted positions. Also unregisters the deleted positions from the document and patches the positions of this presenter. <p> NOTE: Indirectly called from background thread by UI runnable. </p>
 * @param textPresentation the text presentation or <code>null</code>, if the presentation should computed in the UI thread
 * @param addedPositions the added positions
 * @param removedPositions the removed positions
 */
public void updatePresentation(TextPresentation textPresentation,HighlightedPosition[] addedPositions,HighlightedPosition[] removedPositions){
  if (fSourceViewer == null)   return;
  if (isCanceled())   return;
  IDocument document=fSourceViewer.getDocument();
  if (document == null)   return;
  String positionCategory=getPositionCategory();
  List removedPositionsList=Arrays.asList(removedPositions);
  try {
synchronized (fPositionLock) {
      List oldPositions=fPositions;
      int newSize=fPositions.size() + addedPositions.length - removedPositions.length;
      List newPositions=new ArrayList(newSize);
      Position position=null;
      Position addedPosition=null;
      for (int i=0, j=0, n=oldPositions.size(), m=addedPositions.length; i < n || j < m; ) {
        while (position == null && i < n) {
          position=(Position)oldPositions.get(i++);
          if (position.isDeleted() || contain(removedPositionsList,position)) {
            document.removePosition(positionCategory,position);
            position=null;
          }
        }
        if (addedPosition == null && j < m) {
          addedPosition=addedPositions[j++];
          document.addPosition(positionCategory,addedPosition);
        }
        if (position != null)         if (addedPosition != null)         if (position.getOffset() <= addedPosition.getOffset()) {
          newPositions.add(position);
          position=null;
        }
 else {
          newPositions.add(addedPosition);
          addedPosition=null;
        }
 else {
          newPositions.add(position);
          position=null;
        }
 else         if (addedPosition != null) {
          newPositions.add(addedPosition);
          addedPosition=null;
        }
      }
      fPositions=newPositions;
    }
  }
 catch (  BadPositionCategoryException e) {
    JavaPlugin.log(e);
  }
catch (  BadLocationException e) {
    JavaPlugin.log(e);
  }
  if (textPresentation != null)   fSourceViewer.changeTextPresentation(textPresentation,false);
 else   fSourceViewer.invalidateTextPresentation();
}

Fixed version (ground truth):
/** 
 * Invalidate the presentation of the positions based on the given added positions and the existing deleted positions. Also unregisters the deleted positions from the document and patches the positions of this presenter. <p> NOTE: Indirectly called from background thread by UI runnable. </p>
 * @param textPresentation the text presentation or <code>null</code>, if the presentation should computed in the UI thread
 * @param addedPositions the added positions
 * @param removedPositions the removed positions
 */
public void updatePresentation(TextPresentation textPresentation,HighlightedPosition[] addedPositions,HighlightedPosition[] removedPositions){
  if (fSourceViewer == null)   return;
  if (isCanceled())   return;
  IDocument document=fSourceViewer.getDocument();
  if (document == null)   return;
  String positionCategory=getPositionCategory();
  List removedPositionsList=Arrays.asList(removedPositions);
  try {
synchronized (fPositionLock) {
      List oldPositions=fPositions;
      int newSize=fPositions.size() + addedPositions.length - removedPositions.length;
      List newPositions=new ArrayList(newSize);
      Position position=null;
      Position addedPosition=null;
      for (int i=0, j=0, n=oldPositions.size(), m=addedPositions.length; i < n || position != null || j < m || addedPosition != null; ) {
        while (position == null && i < n) {
          position=(Position)oldPositions.get(i++);
          if (position.isDeleted() || contain(removedPositionsList,position)) {
            document.removePosition(positionCategory,position);
            position=null;
          }
        }
        if (addedPosition == null && j < m) {
          addedPosition=addedPositions[j++];
          document.addPosition(positionCategory,addedPosition);
        }
        if (position != null)         if (addedPosition != null)         if (position.getOffset() <= addedPosition.getOffset()) {
          newPositions.add(position);
          position=null;
        }
 else {
          newPositions.add(addedPosition);
          addedPosition=null;
        }
 else {
          newPositions.add(position);
          position=null;
        }
 else         if (addedPosition != null) {
          newPositions.add(addedPosition);
          addedPosition=null;
        }
      }
      fPositions=newPositions;
    }
  }
 catch (  BadPositionCategoryException e) {
    JavaPlugin.log(e);
  }
catch (  BadLocationException e) {
    JavaPlugin.log(e);
  }
  if (textPresentation != null)   fSourceViewer.changeTextPresentation(textPresentation,false);
 else   fSourceViewer.invalidateTextPresentation();
}