Adding DataTipRows - I can't set VALUE of new DataTipRows

p = trisurf(triangles,Points(:,1), Points(:,2), Points(:,3))

Now, I would like to add new DataTipRows:

>> Labels = repmat({'LL'},size(p.XData,1),size(p.XData,2)); % Creates cell array in same size with Xdata
row = dataTipTextRow('L',Labels,'auto');
p.DataTipTemplate.DataTipRows(end+1) = row;

Error using matlab.graphics.datatip.DataTipTemplate/set.DataTipRows

Value must be compatible with the data source.

>> size(triangles)

ans = 1527252 3