I’m afraid not. The help page is really outdated and a rework is one of the top priorities on my todo list 
I think one of the easiest ways to do it is by utilizing the blur functionality.
Give your wrapping element (div) a blur class. Then make sure that you set the following css style:
.wrapper.blur .content{
display: none;
}
Where .wrapper and .content can be any classname corresponding to the correct elements.
so something like this would work:
<div class='blur wrapper'>
<div class='header'>this is a tab</div>
<div class='content'>This is hidden by default :)</div>
</div>
This way you have both the click and the unblur hotkey functionality for showing the content. When a user clicks or presses the hotkey it will remove the class, making the content visible to the user.

after clicking it, it does push further than the background boundaries, but that’s just a small problem ^^
.
I think it’s pretty good as it is already, but mainly right now I just want to add audio clips for the rest of the vocab. Busy focusing on studying & working on other sets right now though.