How to open a Shiny app from within an RStudio Gadget

I am working on a package that bundles a set of apps, and I want to have an RStudio addin that allows you to select the apps based on a categorization. This app is a shiny gadget, which is a special mini-version of a shiny app.

The problem is that :

• I can't use runApp from within another app, that's giving errors.
• I can't return the app that I want to launch, because I tried and it didn't do anything.

Inside a gadget server function I have following code:

observeEvent(input$done,{
      theapp <- shinyAppDir("Dir/to/app")
      stopApp(theapp)
    })

But to no avail. I can catch the app as a return value, but somehow it doesn't open automatically.