You can most likely organize your content in such a way that the filter stays in place. One option could be to wrap your H List box with H Scroll Box
Names Default To Here(1);
New Window("Example",
	Outline Box("Picker",
		H Scroll Box(
			Size(200),
			H List Box(
				H List Box(Text Box("Label:"), Text Edit Box(Char(213))),
				H List Box(Text Box("Label:"), Text Edit Box(Char(213))),
				H List Box(Text Box("Label:"), Text Edit Box(Char(213))),
				H List Box(Text Box("Label:"), Text Edit Box(Char(213))),
				H List Box(Text Box("Label:"), Text Edit Box(Char(213)))
			),
			<<Set Auto Stretching(1, 1)
		)
	)
);

 
					
				
			
			
				
	-Jarmo