Can not close an editor tab in eclipse
<p>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 <strong>right RED box</strong> 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 <strong>left RED box</strong>).</p>

<p>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: </p>

<blockquote>
  <p>Eclipse IDE for Java Developers
  Version: Mars.2 Release (4.5.2)
  Build id: 20160218-0600</p>
</blockquote>

<p><a href="https://i.stack.imgur.com/rOMr4.png" rel="noreferrer"><img src="https://i.stack.imgur.com/rOMr4.png" alt="Screenshot"></a></p>