I am working in SQL Server Management Studio. I can no longer see more than one tab at a time.
If I have a script open and start a new query, SSMS closes my open script.
If I open from file and select multiple scripts; it opens the first, closes it and opens the next, repeatedly until only the final file selected is open.
This began yesterday after I played with the dock settings of my query screen.
You've probably (somehow) ended up with "Reuse current document window, if saved" ticked, as below:
From Tools->Options, Top option on right hand side.
Untick it.
来源：https://stackoverflow.com/questions/26238487/sql-server-management-studio-tabbed-documents