Eclipse Add Tomcat server cannot enter server name

I was trying to add Tomcat 7 in my Eclipse in Ubuntu. When I click ' Add new server ' in Eclipse and select ' Tomcat v7.0 server ', the field ' Server Name ' is blank and I cannot ty PE in anything in that textbox as shown below:

What I do before is I deleted a tomcat 7 servers from Eclipse and I were trying to reinstall Tomcat 7. But it doesn ' t allow me to type anything in that TextBox and I cannot proceed to the "Next" button. My environment is Ubuntu Linux and Eclipse for Java EE.

Here are the workaround that worked for Me:close Eclipse in {workspace-directory}/.metadata/.plugins/org.eclipse.core.run Time/.settingsdelete
The following files:

Org.eclipse.wst.server.core.prefs org.eclipse.jst.server.tomcat.core.prefs Restart Eclipse