I've missed this feature. Didnt' found an option in the ide cfg to check.
It's there, though not where you'd expect. Select Tools->Options" and, in the dialog, under "Environment", "Window". The option is called "Show complete component palette", and it's rather badly placed off to the right.
That is a different feature though.
The OT afaik talks about the tabs of the page control. And having the tabs shown multiline.
The existing features relates to the icons on each page of the pagecontrol.
If there are like 50 components on one single tab, then the component-icons are shown multiline (always). Normally that triggers are vertical scrollbar. But with that option, the main IDE bar extends it height, so that several rows of icons become visible at the same time.