Active upper slider obscured when close to lower, then reverse

When using the sliders to select e.g. a Headphone source between $10 and $100, the slider for the upper range disappears behind the slider for the lower range, rendering it invisible and impractical to use within its useful range. After this initial slide, the situation reverses with the lower slider disappearing under the upper, rendering it invisible and impractical to use.

This kind of UI issue can depend on client dimensions, but this does not appear to be the case since this element behaves this way when not limited by window size.

A simple, but imperfect, fix would be to have the active slider always on top.