When starting my latest RStudio version (1.2.1335), I can choose 'Check for Updates' from the Help menu and all is working fine. However, after starting and closing a Shiny application, this option is gone from the Help menu. Only restarting the IDE solves this issue again.
How to reproduce:
Create New File > Shiny Web app ...
Check Help > Check for Updates << option is available
Thanks for taking the time to investigate this issue. Would you mind filing this as a bug report at https://github.com/rstudio/rstudio/issues, so we don't lose track of this?