• Electron Version: 2.0.7 and 3.0.0-beta.6
• Operating System (Platform and Version): Mac OS High Sierra 10.13.6
• Last known working Electron version: none

Expected Behavior
Dialog box message should be read out by Voice Over

Actual behavior
Dialog box message is not read out by Voice Over

To Reproduce
Turn on Voice Over and start this starter electron app. Notice how the message 'hello there' in the dialog box is not read out by voice over.
https://gist.github.com/isidorn/326fd5a14ccb7eec19f7e5a820327143

Original issue in vscode microsoft/vscode#55585