diff --git a/src/backends/plotlyjs.jl b/src/backends/plotlyjs.jl
index 1482b717..127aef52 100644
--- a/src/backends/plotlyjs.jl
+++ b/src/backends/plotlyjs.jl
@@ -38,7 +38,7 @@ function _series_updated(plt::Plot{PlotlyJSBackend}, series::Series)
     end
     PlotlyJS.restyle!(
         plt.o,
-        findfirst(plt.series_list, series),
+        findfirst(isequal(series), plt.series_list),
         kw
     )
 end
diff --git a/src/plot.jl b/src/plot.jl
index 9d0ee6c4..ccce63d1 100644
--- a/src/plot.jl
+++ b/src/plot.jl
@@ -283,11 +283,11 @@ end
 
 function plot(sp::Subplot, args...; kw...)
     plt = sp.plt
-    plot(plt, args...; kw..., subplot = findfirst(plt.subplots, sp))
+    plot(plt, args...; kw..., subplot = findfirst(isequal(sp), plt.subplots))
 end
 function plot!(sp::Subplot, args...; kw...)
     plt = sp.plt
-    plot!(plt, args...; kw..., subplot = findfirst(plt.subplots, sp))
+    plot!(plt, args...; kw..., subplot = findfirst(isequal(sp), plt.subplots))
 end
 
 # --------------------------------------------------------------------
diff --git a/src/plotattr.jl b/src/plotattr.jl
index 7313b2ce..42e3edf5 100644
--- a/src/plotattr.jl
+++ b/src/plotattr.jl
@@ -46,7 +46,7 @@ function plotattr(attrtype::Symbol, attribute::AbstractString)
     attribute = Symbol(lookup_aliases(attrtype, attribute))
 
     desc = get(_arg_desc, attribute, "")
-    first_period_idx = findfirst(desc, '.')
+    first_period_idx = findfirst(isequal('.'), desc)
     typedesc = desc[1:first_period_idx-1]
     desc = strip(desc[first_period_idx+1:end])
     als = keys(filter((_,v)->v==attribute, _keyAliases)) |> collect |> sort