How to fit multiple children to available space (and distribute available space evenly)?

[bluenote10]

Consider the following use case: In the following I have two lists modeled via child_window. I want the whole app to exactly fit into the available vertical space, i.e., the two lists should just be as high as necessary. Both lists should equally use up the available space.

Currently all I have is using fixed sizes for the children, which means it doesn't scale to the available vertical space:

Reproduction code

import dearpygui.dearpygui as dpg

dpg.create_context()
dpg.create_viewport(title="Example", width=800, height=600)


with dpg.window() as primary_window:

    dpg.add_text("Some UI element(s) before first list:")

    # First child
    with dpg.child_window(height=300):
        for i in range(100):
            dpg.add_selectable(label=f"Lot's of elements in first list ({i})")

    dpg.add_text("Some UI element(s) before second list:")

    # Second child
    with dpg.child_window(height=300):
        for i in range(100):
            dpg.add_selectable(label=f"Lot's of elements in second list ({i})")

    dpg.add_text("Some UI element(s) as a footer that should also be visible")


dpg.setup_dearpygui()
dpg.show_viewport()
dpg.set_primary_window(primary_window, value=True)
dpg.start_dearpygui()
dpg.destroy_context()

If I don't specify fixed heights for the children and rather rely on autosize_y it doesn't work either, because the first child will already use up all available space, and the second child will have a height of zero and neither is the footer visible without scrolling down (basically I don't want any scrolling on the outer window):

Any ideas how this could be solved?