Java- jpanel.removeAll does not remove components

My problem is that I create JPanels with buttons inside. When I press a button, I do a removeAll, but the window is not cleaned, but I have to move the scroll bar a bit so that everything is cleared, it's as if it's was not updated.

    public void clean () {// In theory, this should leave the JPanel clean, but that is not the case.
jpActivitiesAll.removeAll ();
jpActivitiesAll.validate ();

public void actionPerformed (ActionEvent e) {
String actionCommand = e.getActionCommand ();
switch (actionCommand) {


"SHOWIN" box: // C is an interface button that works properly

this.model.obteProximesActivitats (); ();