When color picker is selected on gradient editor window it closes automatically and color picking option gets disabled on Mac

Steps to Repro:
1. Create a new project or open attached project
2. Hierarchy window > right click
3. Effects > particle system
4. Goto particle system's main module's Start color property
5. Click on the drop-down arrow next and change it to gradient
6. Click on the color strip to open gradient editor window
7. Click on dropper icon to pick a color

Actual Result:
1. Unable to pick a color
2. Gradient editor window closes

Occurring on:
Mac Only

Occurring with:
2018.3.0a5, 2018.3.0a4, 2018.3.0a1, 2018.2.0f2, 2018.2.0b1, 2018.1.0b1, 2018.1.0a7

Working with:
2018.2.0a5