The Advanced Icon Hiding Options: Explained

Enable button
If this option is enabled and the Automatic Icon hiding method is selected, Simply Transparent will show a button in the top-left corner instead of your icons. To make your icons show, click the button.

Hide/Show Responsiveness
Here you have the ability to make icon hiding more or less responsive. One quick note though: The more responsive you make this, the more Simply Transparent uses your CPU.