FM2019 - Can't launch the ExtendScript IDE

Hi,

FrameMaker 2019, v15.0.1.430, installed with several previous versions.

The File > Script > New Script command does nothing. I can run a script with File > Script > Run. If I launch the IDE with FM2015 and switch the target to FM2019, again I can run a script. Any ideas why I can't launch the toolkit with FM2019?

Thanks,

Russ