Suggestion on Qt Documentation "All Classes" layout

In Qt 4.8 html documentation the "All Classes" html page has three columns (see Qt48_layout.png) while in Qt 5 it contains only one column (see Qt5_layout.png), which makes the "all classes" list long and hard to navigate.

The suggestion is to get the three column layout back. If needed it could be optional to the user e.g. "click here for different layout", or it could depend on the page width i.e. 3 columns will be rendered only when they fit.

Our specific use case concerns offline html documentation (created with make html_docs), but the same applies to online documentation (http://doc.qt.io/qt-5/classes.html) and Qt Assistant too.