Q:

How to force a line break in a legend of a boxplot?

I need help to skip lines in the legend of boxplots : I have a plot with two boxplots, and each of them has a legend to long to fit on a single line.
I tried this, X being my matrix of data (two colums) :
boxplot(X,'Labels',{'1stpartofthelegend\newline2ndpartofthelegend','1stpartofthelegend\newline2ndpartofthelegend})

This solution works in other types of plots, like a plotspread plot so I don't understand why it is not working here ?
I found this question, but the solutions are not working for me, maybe because I have a more recent version (R2018b).
I actually want to add my boxplots over a plotpsread plot, but when I do that the legends of the boxplots win over the legends of the plotspread (even if I add boxplots without legends, the previous legends of the plotspread are replaced by "1" and "2"). So preventing the boxplot to erase the previous legend would be a nice solution but as I failed to do that I tried to find another way.
Thank you for your help

A:

You want to set the 'Labels' of the boxplot for multiple lines. So use a cell of cells:
Lbl = { {'1st entry (1st line)','2nd entry (1st line)'},...
        {'1st entry (2nd line)','2nd entry (2nd line)'} };
boxplot(rand(100,2),'Labels',Lbl)

EDIT
LaTeX commands work in the title and labels but apparently there is no interpreter or TickLabelInterpreter  property for boxplot-Labels:

Error using internal.stats.parseArgs (line 42)
Invalid parameter name: TickLabelInterpreter.

