Show old legend button in the HTML5Viewer (version 2.9)

In the old HTML5Viewer there was a single button in the layerlist which could be used to show the legend. In the new viewer you must use a pulldownmenu in which there is an option to show the legend.

 

I would like the old button back. I am sure I saw this was possible once. Unfortunately I cannot find this option in the Manager or in the desktop.json file.

 

Does anybody know a way to get this button back?

 

Many thanks in advance.

 

Luuk