Q:

Can not close an editor tab in eclipse

I remember when I click an editor in Eclipse, there would be a cross or maximize icon in the upper-right corner in the editor tab, as shown in the right RED box in the picture. I do not know what changes I did and could care less as the close icon is no longer there (in the left RED box).
Does anyone have any idea how to restore the close button back? I tried to reset all Perspectives, and clicked left/right buttons, but nothing changed. The Eclipse version is: 

Eclipse IDE for Java Developers
  Version: Mars.2 Release (4.5.2)
  Build id: 20160218-0600

A:

In the file menu(File>>Close All), click the close All item. Eclipse will close all the existing tabs, when you reopen the code. The close button will come back.

