code: protected boolean updateFileWindow(Dim.SourceInfo sourceInfo) {
          String fileName = sourceInfo.url();
          FileWindow w = getFileWindow(fileName);
          if (w != null) {
              w.updateText(sourceInfo);
              w.show();
              return true;
          }
          return false;
      }
docs: Update the source text for <code>sourceInfo</code>. This returns true
  if a {@link FileWindow} for the given source exists and could be updated.
  Otherwise, this does nothing and returns false.
  @param sourceInfo the source info
  @return true if a {@link FileWindow} for the given source exists
  and could be updated, false otherwise.