message: don't lose focus for pdf tab preview
diff: @@ -96,7 +96,13 @@ export class Viewer {
  client.websocket.close()
  }
  this.clients[pdfFile.toLocaleUpperCase()] = {type: 'tab'}
  - vscode.commands.executeCommand('vscode.previewHtml', uri, column, path.basename(pdfFile))
  + const window = vscode.window.activeTextEditor
  + vscode.commands.executeCommand('vscode.previewHtml', uri, column, path.basename(pdfFile)).then(success => {
  + if (success && window) {
  + vscode.window.showTextDocument(window.document)
  + }
  + return true
  + })
  this.extension.logger.addLogMessage(`Open PDF tab for ${pdfFile}`)
  }
  