• Start Aptana and navigate the application menu to: Help → Software Updates → Find and Install… → Search for new features to install → New remote site…
• Name: “Spket”, Url: “​​http://www.spket.com/update/​​”
• Restart Eclipse
• Watch this ​​Spket​​ to see how to easily add Ext code assist (you can point it at the latest /src/ext.jsb to keep code assist up to date with the latest Ext version). The steps are basically:

• Window → Preferences → Spket
• Enter “ExtJS” and click OK
• Select “ExtJS” and click “Add Library”, then choose “ExtJS” from the dropdown
• Select “ExtJS” and click “Add File”, then choose the “ext.jsb” file in your “./ext-2.x/source” directory
• Set the new ExtJS profile as the default by selecting it an clicking the “Default” button on the right-hand side of the “JavaScript Profiles” dialog.
• Restart Eclipse
• Create a new JS file and type: Ext. and you should get the Ext Code completion options.