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= DevFaqWindowsTopComponentLookup
:jbake-type: wiki
:jbake-tags: wiki, devfaq, needsreview
:jbake-status: published
:keywords: Apache NetBeans wiki DevFaqWindowsTopComponentLookup
:description: Apache NetBeans wiki DevFaqWindowsTopComponentLookup
:toc: left
:toc-title:
:syntax: true

=== Why does `TopComponent` have a `getLookup()` method? What is it for?

The windowing system is what manages link:DevFaqTrackGlobalSelection.asciidoc[global selection].  In olden times, selection meant the activated link:DevFaqWhatIsANode.asciidoc[Node].

In modern NetBeans, the global selection is really whatever objects are in the focused  `link:DevFaqWindowsTopComponent.asciidoc[TopComponent]`'s link:DevFaqLookup.asciidoc[Lookup].  It so happens that most standard TopComponents display `link:DevFaqWhatIsANode.asciidoc[Node]`s - so for most `TopComponent`s, the component's `Lookup` is just proxying the `Lookup` of the selected Node.

Rather than thinking of the selection as some specific object or Node, it is more useful to think of it as a grab bag of stuff provided by whatever component happens to have focus.  If you use `link:DevFaqTrackGlobalSelection.asciidoc[Utilities.actionsGlobalContext()]`, you do not have to track all the different grab-bags of stuff provided by different components - you can get one grab bag of stuff which whose content will simply change (notifying you in the process) when focus moves to a different component.

So the `TopComponent`'s `Lookup` is a way to provide your particular grab bag of stuff - it can be the lookup of a `Node` if you want, or it can be/contain whatever else or in addition you'd like to put there.

=== Apache Migration Information

The content in this page was kindly donated by Oracle Corp. to the
Apache Software Foundation.

This page was exported from link:http://wiki.netbeans.org/DevFaqWindowsTopComponentLookup[http://wiki.netbeans.org/DevFaqWindowsTopComponentLookup] , 
that was last modified by NetBeans user Admin 
on 2009-11-06T16:06:27Z.


*NOTE:* This document was automatically converted to the AsciiDoc format on 2018-02-07, and needs to be reviewed.