Documentation

Height

This property controls the height of the legend block.

The default value for the property is "0" which automatically resizes the legends block based on algorithm. 

By changing it, you can alter the layout of the legends, meaning that they can be laid out in one or multiple columns.

graph-formatting-legend-height

Currently if you see 3 dots in the legends block, it means that some of your legends did not fit in the block. To see the hidden legends, you have to change the Height property, or resize the chart container