There is no delete button here !

This bugged me all day. So I ended up following aditya-srinivasan's answer on http://superuser.com/questions/315949/dont-exit-full-screen-when-pressing-escape-in-apps-like-safari-on-lion/1074826#1074826

Basically, you need to get a Keyboard Modifier : 'karabiner' in this instance. The XML file on the example was for Safari, I modified it to work for Opera..

This is the same as the aditya-srinivasan answer targeting Opera. Follow the same instructions and use this as the contents for the XML file. You'll get the option at the top of the first tab after 'reloading the XML file'

<?xml version="1.0"?>
<root>
	<item>
  <!-- ============================================================ -->
  <appdef>
    <appname>OPERA</appname>
    <equal>com.operasoftware.Opera</equal>
  </appdef>
  
    <name>Escape to Option + Escape on Opera</name>
    <identifier>private.Opera_escape</identifier> 
    <only>OPERA</only>
    <autogen>__KeyToKey__ KeyCode::ESCAPE, KeyCode::ESCAPE, ModifierFlag::OPTION_L</autogen>
  </item>
  <!-- ============================================================ -->
</root>

See aditya-srinivasan answers on the downloading https://pqrs.org/osx/karabiner/index.html.en

Bump...

This really is painful while using Opera