Tmap legend ignores is.potrait=FALSE

[angela_italy]

Hello,
I am struggling with the legend in tmap
I would like to have a legend on the bottom and horizontally but I am not able to achieve it.
Moreover, it is also ignoring the title of first shape I specify.

This is my code

tm_shape(shape)+
  tm_polygons(col="gold3",
              alpha=0.2,
              title="Shape 1",
              legend.is.portrait = FALSE,
              legend.show=TRUE)+
  tm_shape(out_arid_sf)+
  tm_bubbles(col="fit_sperror",
             size="fit_sperror",
             style="cont",
             alpha=0.5,  
             breaks=mybreaks,
             midpoint = NA,
             legend.size.show = FALSE,
             palette=mypalette,
             title.col="Fitted Values",
             size.lim = c(min(out_arid_sf$fit_sperror),max(out_arid_sf$fit_sperror))) +
  tm_layout(legend.outside = TRUE,
            legend.title.size=1.5,
            legend.text.size=1,
            legend.outside.size = 0.35,
            legend.outside.position = "bottom")

I found a similar post on stackoverflow but in my case the legend.is.potrait option does not work ..

Thanks for your help