What ExtJS event for when click tree and tab and different panel displayed

Question

I have a treepanel and a content area to the right, where tab panels display.

When a tree node is clicked, I show a tab panel in content area to the right, where each tab displays different info about the tab topic.

Let's say I click a tree node, then on the second tab for its tab panel in the content area to the right.

Then I click a different tree node. That newly clicked nodes tab panel now displays in the content area to the right.

What event can I listen to in order to know when the previous node's tab panel is no longer visible? Hide does not work. Deactivate does not work. Wondering how I can detect this.

Answer 1

At least in my case, it looks like destroy event does the trick.