max_rows apparently not working

[bchoubert]

When setting up the 'sample' project with these given properties :
widget_margins: [10, 10],
widget_base_dimensions: [140, 140],
shift_larger_widgets_down: true,
max_cols: 6,
max_rows: 3,,
the property max_rows is either not repected at all by the code, or glith the interface.

No error or warning in the console, I think this problem is caused by old code.

Picture showing that the 'max_rows' option is not respected :

Picture showing the glitch obtained somtimes obtained by dragging some widgets with the 'max_rows' option set :