public static PsiElement findPrevCell(PsiElement startElement) {
    PsiElement el = PsiTreeUtil.prevLeaf(PsiTreeUtil.getDeepestFirst(startElement));
    while (el != null) {
      if (isBlockCell(el)) {
        return el;
      }
      el = PsiTreeUtil.prevLeaf(el);
    }
    return null;
  }
public static PsiElement findPrevCell(PsiElement startElement)