Change images with buttons - Google Looker Studio

[luapuccinelli]

I'm using Looker Studio, and I have a question:

I have 2 buttons in my dashboard, each one is an client of a group. I try an function to change the logo by pressing the buttons. 

When button 1 is pressed, logo 1 appears, when button 2 is pressed, logo 2 appears and when no one of the buttons is pressed, logo 3 appears.

I've try this function:

CASE

WHEN BUTTON 1 = TRUE THEN LOGO 1

WHEN BUTTON 2 = TRUE THEN LOGO 2

ELSE LOGO 3

END

And it works partially, when button 1 is pressed, shows logo 1 same as button 2 , but when no one of then is pressed, appears logo 1 and 2, not logo 3.

How can I fix this?