Parameter search input field size changes on changing a parameter value in Blend Tree. After changing value it comes in its original size.

Steps to repro:
1. Create a new project.
2. Assets menu > Create > Animator Controller > Open.
3. Create a new Blend Tree > Open the Blend Tree.
4. Change the value using the slider.

Actual result:
Search input field size changes on changing a parameter value.

Expected ReSult:
Search input field size should not change.

Reproducible on:
2020.1.0b3.

Working Fine in:
2020.2.0a5, 2020.1.0b2, 2019.3.0f3.

Environment:
Windows and Mac.