1. If you're on fullscreen mode, switch to windowed. And if you're on windowed mode, switch to fullscreen.

2. Move the magnifying glass around the scroll until you see the symbol that matches the first colored button on top.

3. Put the symbol in the center of the magnifying glass. When you click, the colored button is supposed to light up. But in some cases, clicking doesn't do anything, so obviously there's a glitch.

4. Here's the workaround -- MOVE your cursor downward, till the top of the magnifying glass covers the symbol, and THEN click.