How to fix:
Close all SSMS windows, and find your SQL Mgt Studio EXE file, mine was in:
C:\Program Files (x86)\Microsoft SQL Server Management Studio 18\Common7\IDE
If you cant find it, right click your shortcut you use to open SSMS and go Properties > Open File Location
Once you have found this, you will also find a file called
Ssms.exe.config, open up a Notepad in Administrator Mode, and edit this file
You will then need to find an xml tag called
<AppContextSwitchOverrides>, and
APPEND (not replace) the following exactly:
;Switch.System.Windows.Interop.MouseInput.OptOutOfMoveToChromedWindowFix=true; Switch.System.Windows.Interop.MouseInput.DoNotOptOutOfMoveToChromedWindowFix=true
Via:
https://docs.microsoft.com/answers/answers/274201/view.html