Scrollable content does not respond to size changes, only when reopoening the portal overlay.

[Elixell]

Describe the bug

Hi, thanks for the awesome work with Portal,.

I want to have a popup menu which responds to the window size changes, in my example a vertical size change should make the content scrollable if there is not enough space to render the children. My problem is that in the portal follower this doesn't happen despite the build clearly invoked. After reopening the portal the scrolling is fine.
I am not sure it is a bug or i am doing something wrong.
I attached a sample which shows the portal and the same list without the portal.

To Reproduce

 return Scaffold(
      body: Portal(
        child: Row(
          crossAxisAlignment: CrossAxisAlignment.start,
          mainAxisAlignment: MainAxisAlignment.start,
          children: [
            PortalTarget(
              visible: isVisible,
              anchor: const Aligned(
                target: Alignment.bottomRight,
                follower: Alignment.topRight,
                widthFactor: 1.0
              ),
              portalFollower: Card(
                child: ListView(
                  children: List.generate(20, (index) => Container(
                    height: 30,
                    color: Colors.white,
                    child: const Text("Test"),
                  ))
                ),
              ),
              child: const Text("This is portal")
            ),
            SizedBox(
                width: 150,
                child: TextButton(
                  onPressed: () => setState(() {isVisible = !isVisible;}),
                  child: const Text("Show or hide the portal ")
                )
            ),
            Expanded(
              child: ListView(
                shrinkWrap: true,
                children: List.generate(20, (index) => Container(
                  height: 30,
                  color: Colors.white,
                  child: const Text("Test"),
                ))
              ),
            ),
          ],
        ),
      )
    );

portal_scroll.mp4

[fzyzcjy]

Maybe related to #53?

[Elixell]

Yes same issue, thanks for pointing out.

[fzyzcjy]

You are welcome