Steps to Reproduce

Whenever I show a Slider in a ModalRoute and the user dismisses that modal while the slider is showing its value indicator, the value indicator is "left behind", i.e. the indicator overlay stays on the screen, indefinitely.
This is very ugly and confusing.

Expected results: slider should completely disappear when the modal is closed.

Actual results: the value indicator stays visible indefinitely at the top of the screen.

Note

The label indicator needs to be visible while the modal is being closed, i.e. to reproduce: have a slider with a label and change its value by tapping, then immediately close the modal..

This happens with both v1 and v2 sliders.

Flutter v1.18.0-9.0
// master versions since the v2 slider was introduced