Components disappear when window is dragged (and browser has no scrollbar)

My app has lots of subwindows. Often the bottom of those windows ends up being outside the viewable browser area.

When such a window is dragged, any component on the top (such as a menu bar) disappears - and the browser shows no scrollbar!
The top (e.g. menu bar can) only be brought back by either:

  • zooming all the way out and back in
  • moving the window all the way to the top to “scroll” the manu bar back in.

I have tried all kinds of things imaginable, but clearly I am missing the solution :-).

Is there a way to either:

  • force the browser to show a scroll bar?
  • or avoid this problem in the first place (I tried making the main window huge, but that doesn’t help)

I have distilled the essential problem into this tiny app:

public class HelloVaadin extends com.vaadin.Application  {
	public void init() {
		Window main= new Window("Window drag test");
		VerticalLayout v = new VerticalLayout();
		v.addComponent(new Label("This label is on top and should stay there - but it doesn't (and the browser will get no scroll bar)"));	
		Window win = new Window("Window with bottom outside of viewing area");
		win.addComponent(new Label("When the window is dragged, the top label disappers... (until moved all the way to the top)"));

Screen shot when starting the test app above:

When starting to drag the window:

Thanks a lot for any help!

I can get scrollbars to appear in the browser with:

main.setHeight( "2000px");

But moving that scrollbar does not move the label back in either.