diff --git a/R/step1_helper_facets.R b/R/step1_helper_facets.R
index a88d2d9c..fa2fd05e 100644
--- a/R/step1_helper_facets.R
+++ b/R/step1_helper_facets.R
@@ -336,7 +336,7 @@ step1_rearrange_facets = function(tmo, o) {
 				if (is.null(sunit)) sunit = o$unit
 				shape.unit <- ifelse(sunit=="metric", "km", ifelse(sunit=="imperial", "mi", sunit))
 				u = paste(shape.unit, shape.unit)
-				shp[[v]] = shp[[v]] / units::set_units(shp$AREA, u, mode = "standard")
+				if (is.numeric(shp[[v]])) shp[[v]] = shp[[v]] / units::set_units(shp$AREA, u, mode = "standard")
 			}
 		}
 		
diff --git a/R/step4_helper_legends.R b/R/step4_helper_legends.R
index c88b91f9..94f4e689 100644
--- a/R/step4_helper_legends.R
+++ b/R/step4_helper_legends.R
@@ -55,7 +55,7 @@ step4_plot_collect_legends = function(tmx) {
 				# find shared legends
 				
 				icon_scales = vapply(legs2, function(l) {
-					as.numeric(l$icon_scale)
+					as.numeric(l$icon_scale[1])
 				}, FUN.VALUE = numeric(1))
 				icon_scale = if (any(icon_scales != 1)) icon_scales[which(icon_scales != 1)[1]] else 1
 				
diff --git a/R/v4_v3.R b/R/v4_v3.R
index 47ff09c4..ee717fc9 100644
--- a/R/v4_v3.R
+++ b/R/v4_v3.R
@@ -21,6 +21,10 @@ v3_use_component = function(arg = "title", comp = "tm_title", container = "tm_fo
 	message(paste0("[v3->v4] ", container, "(): use ", comp, "() instead of the argument '", arg, "'"))
 }
 
+v3_convert2density = function(layer_fun) {
+	message(paste0("[v3->v4] ", layer_fun, "(): convert2density is deprecated: divide the variable values by the polygon areas manually (obtain the areas with 'sf::st_area()')"))
+}
+
 v3_tm_scale_instead_of_style = function(style, scale_fun, vv, layer_fun, arg_list) {
 	if (scale_fun == "intervals") {
 		arg_list$old = c("style", arg_list$old)