How to click multiple buttons with 1 click

This is a grid of buttons that I have.

Now I can click the buttons no problem. After clicking the buttons, the buttons become 100% opacity.

However, I need to left click once every time I want to click on a button which is pretty annoying. I want to press and hold left mouse button, then drag mouse over multiple buttons, and let go left mouse button to “click” the buttons.

How do I do this?

I would instead use a time range input, will make this easier :slight_smile: