Drag and Drop table object explorer into query window issue Sql Server Management Studio 18.1
Follow this feedback item for updates on the issue:
SSMS Crash when dragging table from Object explorer into new query window

Microsoft SQL Server (Product Manager, Microsoft Azure) responded  ·  Jun 14, 2019
Issue has been identified and a fix is being made. It will be rolled out with the next update of SSMS 18.

In the meantime, you could revert to SSMS 17.9.