How to modify server location Gray in eclipse?

Tomcat Service settings in eclipse
Select window----show view---services to see a panel of services
Double-click Tomcat to enter the Configuration Interface service Locations (Specify the server path (i.e. catalina.base) and deploy path. The Server must is published with the no modules present to make changes.) option dimmed the configuration cannot be changed.
To change, remove all items under Tomcat first. And right-click, clean ... Before you can set ... It turns black again when it starts.

The default options are:
Use workspace metadata (dose not modify Tomcat installation)
The modification options are:
Use Tomcat installation (takes control of Tomcat installation)

This enables the Tomcat server to be launched in Eclipse, and we can also access the Tomcat local admin home page.
Otherwise, you can use Tomcat's start command only under DOS to access the Tomcat local administration home page.

How to modify server location Gray in eclipse?