What is the shortcut key to show/hide tool buttons in PhpStorm?

I am unable to find the shortcut key for this button. And as I do not know the name of this button I cannot search for it.

Here is your answer from official docs

Hiding all tool windows attached to the same tool window bar

Do one of the following:

Press and hold the Alt (for Windows and Linux users) or ⌘ (for macOS users) key, and click hide on the title bar of any of the tool windows attached to the corresponding tool window bar.

Choose Window | Active Tool Window | Hide Side Tool Windows in the main menu. This command hides all the tool windows attached to same tool window bar as the active tool window or the last of the active tool windows.

I find that double tapping Alt key does the trick for me.