I tried this quickly.
The flex grow set to 0 does not always work, because of the order the class is applied. If the node already sets a grow, the class has no chance to change that.
However, I used max-height sucessfully.
First I added a ToggleButton and added a new value, here “UI:hideKeyboard”
Then I created a class called “hidden”. Connect the class: active property to the “UI:hideKeyboard”.
For good measure I set max-width, max-height and flex-grow to 0.
applied the class to the component I wanted to hide
Unfortunately the change to the class didn’t work immediately, so I had to force a rebuild of the GUI in the menu: File → Refresh.
Now the checkbox can switch the keyboard on and off
That worked! I hadn’t noticed the active property of a class before.
I’ve now extended this so that there are two Views, with the second View hidden (and not taking up blank space on the interface). If the user clicks a button, the first View gets hidden and the second View is revealed.
This is a precursor to getting the JUCE tutorial JUCE: Tutorial: Unlock your plugins through online registration working with PGM. Hopefully, the next step, getting JUCE’s OnlineUnlockForm as a custom GUI component, won’t be too difficult. If you’ve got any ideas there, though, that would be great.