You can use browse-url for non-detached applets to go to another applet, and as long as the machine doesn't run low on memory, you can browse back to the original applet

with the browser back button or by calling Applet.browse-backward.

But detached applets don't have a browser, so for them you would just leave the parent applet running.

Why do you want to freeze the parent applet?

{curl 6.0 applet}

|| Use a repository to show how many times this applet has been loaded.

||Define the parameters for the default repository
{persistent-data
    "saved values",
    duration=180days
}

{def tf = {TextField}}

{try
    || Be prepared to catch an exception if repository
    || has not yet been created.

    || Get the value from the repository
    set tf.value = {get-persistent-data "tf value"}

 catch not-found:KeyNotFoundException do
    || The key was not found, so the value has not been stored
    || before.
}


{define-proc {save-on-exit}:void
    || Update the value in the repository
    {set-persistent-data "tf value", tf.value}
    {commit-persistent-data}
}

{register-exit-proc save-on-exit}

{value tf}