Status Bar (Database Engine Query Editor)
Applies to: 
SQL Server
The status bar of Database Engine Query Editor windows can be color coded to indicate which instance of the Database Engine each window is connected to.
Before you begin: Status Bar Colors
To set a server status color in: Object Explorer, Registered Server
To use a status color: Open Query Editor Using a Server Color, Open a Query Editor Specifying a Status Color
This feature works with SSMS version 17.9.1 and earlier.
Status Bar Colors
You can associate a status bar color with a specific server node in either Object Explorer or Registered Servers. The colors can only be specified for server nodes connected to an instance of the Database Engine, not server nodes for other SQL Server technologies. You can also specify a custom status bar color each time you connect a new Database Engine Query Editor window to an instance of the Database Engine. You can then open a query editor window using either the status color defined for the server node, or specify a unique color for that editor window.
Setting a custom status bar color for a server node in Object Explorer must be done when making the connection. To change the color associated with an existing server node, you must disconnect and then reconnect specifying the new color.
Set the Status Color for a Server in Object Explorer
To set a server status color in Object Explorer
In Object Explorer, select the Connect button and then select Database Engine....
On the Connect to Server dialog, select Options >>.
Select the Use custom color check box.
To select the color, select the Select... button.
Select either a basic or custom color, then select OK.
Fill in the rest of the connection information, and then select the Connect button.
Set the Status Color For a Registered Server
To set a server color For a Registered Server
In Registered Servers, right-click the server node and then select Properties....
On the Edit Server Registration Properties dialog, select the Connection Properties tab.
Select the Use custom color check box.
To select the color, select the Select... button.
Select either a basic or custom color, then select OK.
Select the Save button on the Edit Server Registration Properties dialog.
Open An Editor Using a Server Color
To open an editor window using a server color
Right-click a server node in either Object Explorer or Registered Servers, and select New Query.
Alternatively, highlight a server node, and then select the New Query toolbar button.
The status bar in the editor window will use the color defined for the associated server.
Open an Editor Specifying a Status Color
To open an editor window specifying a status color
Open the File menu, select New, and then select Database Engine Query.
On the Connect to Server dialog, select Options >>.
Select the Use custom color check box.
To select the color, select the Select... button.
Select either a basic or custom color, then select OK.
Fill in the rest of the connection information, and then select the Connect button.