message: Exclude optionalArgs for \begin{frame}{title}
diff: @@ -334,10 +334,10 @@ export class SectionNodeProvider implements vscode.TreeDataProvider<Section> {
  caption = 'Untitled Frame'
  captionNode = node.content.filter(latexParser.isCommand).find(subNode => subNode.name.replace(/\*$/, '') === 'frametitle')
  +
  // \begin{frame}(whitespace){Title}
  - if (node.args.length > 0) {
  - caption = this.captionify(node.args[0])
  - }
  + const nodeArg = node.args.find(latexParser.isGroup)
  + caption = nodeArg ? this.captionify(nodeArg) : caption
  } else if (node.name.replace(/\*$/, '') === 'figure' || node.name.replace(/\*$/, '') === 'table') {
  // \begin{figure} \caption{Figure Title}
  captionNode = node.content.filter(latexParser.isCommand).find(subNode => subNode.name.replace(/\*$/, '') === 'caption')
  