Dynamically adding elements to JTaskPane and JTaskPaneGroup

Whenever you dynamically - at runtime - add components to a JTaskPaneGroup, it is very important to revalidate it. Suppose I want to add a JTaskPaneGroup to an existing JTaskPaneGroup (nested JTaskPaneGroups):

// when building the application, creates a JTaskPaneGroup
JTaskPaneGroup parent = new JTaskPaneGroup();

// later, triggered by the user action, add another JTaskPaneGroup
JTaskPaneGroup child = new JTaskPaneGroup();
parent.add(child);
// make sure to revalidate the parent JTaskPaneGroup
// otherwise the user interface may not repaint correctly
parent.revalidate();
parent.repaint();

And here is the result:

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The same applies if you are adding/removing actions, components: make sure to validate!