The BSL on a right click context menu fails to pass the information that the word is in Greek to the BWS. Result the BWS tries to treat it as English and generates no results.
How strange! Of course you can just left-click on the word to run the Bible Word Study, which functions correctly.
I'll report the issue to Development. Thanks!
This will be fixed in 5.0b Beta 2 for beta testers, and in general when 5.0b ships to the stable channel.