diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 27ab1c5..d5f9834 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,12 +22,12 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        version: [1.8]
+        version: [1.9]
         arch: [x64]
         os: [ubuntu-22.04] # macos-10.15, windows-2019
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Julia Setup
         uses: julia-actions/setup-julia@v1
         with:
@@ -44,7 +44,7 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       - name: Percy Upload
-        if: ${{ matrix.version == '1.8' }}
+        if: ${{ matrix.version == '1.9' }}
         run: |
           ls ./test/output/ # useful for debugging
           npx @percy/cli upload ./test/output
@@ -53,4 +53,6 @@ jobs:
       - name: Coverage Process
         uses: julia-actions/julia-processcoverage@v1
       - name: Coverage Upload
-        uses: codecov/codecov-action@v3
+        uses: codecov/codecov-action@v4
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
diff --git a/.github/workflows/documenter.yml b/.github/workflows/documenter.yml
index 50f7b3d..4a0b00e 100644
--- a/.github/workflows/documenter.yml
+++ b/.github/workflows/documenter.yml
@@ -25,7 +25,7 @@ jobs:
     # Run on push's or non-draft PRs
     if: (github.event_name == 'push') || (github.event.pull_request.draft == false)
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v1
         with:
           version: 1
diff --git a/.github/workflows/style.yml b/.github/workflows/style.yml
index 42b467f..2ebd63c 100644
--- a/.github/workflows/style.yml
+++ b/.github/workflows/style.yml
@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        julia-version: [1.8]
+        julia-version: [1.9]
     steps:
       - uses: julia-actions/setup-julia@latest
         with:
diff --git a/Project.toml b/Project.toml
index 5bd903b..0e08989 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "MixedModelsMakie"
 uuid = "b12ae82c-6730-437f-aff9-d2c38332a376"
 authors = ["Phillip Alday <me@phillipalday.com>", "Douglas Bates <dmbates@gmail.com>", "contributors"]
-version = "0.3.28"
+version = "0.4.0"
 
 [deps]
 BSplineKit = "093aae92-e908-43d7-9660-e50ee39d5a0a"
@@ -19,11 +19,11 @@ StatsBase = "2913bbd2-ae8a-5f71-8c99-4fb6c76f3a91"
 [compat]
 BSplineKit = "0.15, 0.16, 0.17"
 DataFrames = "1"
-Distributions = "0.21, 0.22, 0.23, 0.24, 0.25"
+Distributions = "0.25"
 KernelDensity = "0.6.3"
 Makie = "0.20"
 MixedModels = "4.14"
 PrecompileTools = "1"
 SpecialFunctions = "1, 2"
-StatsBase = "0.31, 0.32, 0.33, 0.34"
-julia = "1.8"
+StatsBase = "0.33, 0.34"
+julia = "1.9"
diff --git a/src/MixedModelsMakie.jl b/src/MixedModelsMakie.jl
index e1e1b50..870e42c 100644
--- a/src/MixedModelsMakie.jl
+++ b/src/MixedModelsMakie.jl
@@ -36,6 +36,10 @@ export RanefInfo,
        zetaplot,
        zetaplot!
 
+# from https://github.com/MakieOrg/Makie.jl/issues/2992
+const Indexable = Union{Makie.Figure,Makie.GridLayout,Makie.GridPosition,
+                        Makie.GridSubposition}
+
 include("utilities.jl")
 include("shrinkage.jl")
 include("caterpillar.jl")
@@ -48,7 +52,7 @@ include("recipes.jl")
 
 @setup_workload begin
     model = fit(MixedModel, @formula(reaction ~ 1 + days + (1 + days | subj)),
-                MixedModels.dataset(:sleepstudy))
+                MixedModels.dataset(:sleepstudy); progress=false)
     @compile_workload begin
         caterpillar(model)
         coefplot(model)
diff --git a/src/coefplot.jl b/src/coefplot.jl
index 59a653c..60a02be 100644
--- a/src/coefplot.jl
+++ b/src/coefplot.jl
@@ -1,65 +1,59 @@
 """
-    coefplot(x::MixedModel;
-             conf_level=0.95, vline_at_zero=true, show_intercept=true, attributes...)
-    coefplot(x::MixedModelBootstrap;
-             conf_level=0.95, vline_at_zero=true, show_intercept=true, attributes...)
+    coefplot(x::Union{MixedModel,MixedModelBootstrap}; kwargs...)::Figure
+    coefplot!(fig::$(Indexable), x::Union{MixedModel,MixedModelBootstrap}; 
+              kwargs...)
+    coefplot!(ax::Axis, Union{MixedModel,MixedModelBootstrap};
+              conf_level=0.95, vline_at_zero=true, show_intercept=true, attributes...)
 
 Create a coefficient plot of the fixed-effects and associated confidence intervals.
 
-!!! note
-    This functionality is implemented using [Makie recipes](https://makie.juliaplots.org/v0.15.0/recipes.html)
-    and thus there are also additional auto-generated methods for `coefplot` and `coefplot!` that may be useful
-    when constructing more complex figures.
+Inestimable coefficients (coefficients removed by pivoting in the rank deficient case) are excluded.
+
+`attributes` are passed onto `scatter!` and `errorbars!`.
+
+The mutating methods return the original object.
+
+!!! note 
+    Inestimable coefficients (coefficients removed by pivoting in the rank deficient case) 
+    are excluded.
 """
-function coefplot(x::Union{MixedModel,MixedModelBootstrap};
-                  conf_level=0.95,
-                  vline_at_zero=true,
-                  show_intercept=true,
-                  attributes...)
+function coefplot(x::Union{MixedModel,MixedModelBootstrap}; show_intercept=true, kwargs...)
     # need to guarantee a min height of 150
     fig = Figure(; size=(640, max(150, 75 * _npreds(x; show_intercept))))
-    ax = Axis(fig[1, 1])
-    pl = coefplot!(ax, x; conf_level, vline_at_zero, show_intercept, attributes...)
-    return Makie.FigureAxisPlot(fig, ax, pl)
+    coefplot!(fig, x; kwargs...)
+    return fig
 end
 
-@recipe(CoefPlot, x) do scene
-    return Attributes(; conf_level=0.95, vline_at_zero=true, show_intercept=true)
+"""$(@doc coefplot)"""
+function coefplot!(fig::Indexable, x::Union{MixedModel,MixedModelBootstrap}; kwargs...)
+    ax = Axis(fig[1, 1])
+    coefplot!(ax, x; kwargs...)
+    return fig
 end
 
-function Makie.plot!(ax::Axis, P::Type{<:CoefPlot}, allattrs::Makie.Attributes, x)
-    plot = Makie.plot!(ax.scene, P, allattrs, x)
+"""$(@doc coefplot)"""
+function coefplot!(ax::Axis, x::Union{MixedModel,MixedModelBootstrap};
+                   conf_level=0.95,
+                   vline_at_zero=true,
+                   show_intercept=true,
+                   attributes...)
+    ci = confint_table(x, conf_level; show_intercept)
+    y = nrow(ci):-1:1
+    xvals = ci.estimate
+    xlabel = @sprintf "Estimate and %g%% confidence interval" conf_level * 100
+
+    attributes = merge((; xlabel), attributes)
+    ax.xlabel = attributes.xlabel
+
+    scatter!(ax, xvals, y; attributes...)
+    errorbars!(ax, xvals, y, xvals .- ci.lower, ci.upper .- xvals;
+               direction=:x, attributes...)
+    vline_at_zero && vlines!(ax, 0; color=(:black, 0.75), linestyle=:dash)
 
-    if haskey(allattrs, :title)
-        ax.title = allattrs.title[]
-    end
-    if haskey(allattrs, :xlabel)
-        ax.xlabel = allattrs.xlabel[]
-    else
-        ax.xlabel = @sprintf "Estimate and %g%% confidence interval" (allattrs.conf_level[] *
-                                                                      100)
-    end
-    if haskey(allattrs, :ylabel)
-        ax.ylabel = allattrs.ylabel[]
-    end
     reset_limits!(ax)
-    show_intercept = allattrs.show_intercept[]
     cn = _coefnames(x; show_intercept)
     nticks = _npreds(x; show_intercept)
     ax.yticks = (nticks:-1:1, cn)
     ylims!(ax, 0, nticks + 1)
-    allattrs.vline_at_zero[] && vlines!(ax, 0; color=(:black, 0.75), linestyle=:dash)
-    return plot
-end
-
-function Makie.plot!(plot::CoefPlot{<:Tuple{Union{MixedModel,MixedModelBootstrap}}})
-    model_or_boot, conf_level = plot[1][], plot.conf_level[]
-    ci = confint_table(model_or_boot, conf_level)
-    plot.show_intercept[] || filter!(:coefname => !=("(Intercept)"), ci)
-    y = nrow(ci):-1:1
-    xvals = ci.estimate
-    scatter!(plot, xvals, y)
-    errorbars!(plot, xvals, y, xvals .- ci.lower, ci.upper .- xvals; direction=:x)
-
-    return plot
+    return ax
 end
diff --git a/src/ridge.jl b/src/ridge.jl
index 40fc70d..d2ad163 100644
--- a/src/ridge.jl
+++ b/src/ridge.jl
@@ -1,15 +1,9 @@
-
-@recipe(RidgePlot, x) do scene
-    return Attributes(;
-                      conf_level=0.95,
-                      vline_at_zero=true,
-                      show_intercept=true)
-end
-
 """
-    ridgeplot(x::MixedModelBootstrap;
-              conf_level=0.95, vline_at_zero=true, show_intercept=true,
-              attributes...)
+    ridgeplot(x::Union{MixedModel,MixedModelBootstrap}; kwargs...)::Figure
+    ridgeplot!(fig::$(Indexable), x::Union{MixedModel,MixedModelBootstrap}; 
+              kwargs...)
+    ridgeplot!(ax::Axis, Union{MixedModel,MixedModelBootstrap};
+              conf_level=0.95, vline_at_zero=true, show_intercept=true, attributes...)
 
 Create a ridge plot for the bootstrap samples of the fixed effects.
 
@@ -18,84 +12,89 @@ Densities are normalized so that the maximum density is always 1.
 The highest density interval corresponding to `conf_level` is marked with a bar at the bottom of each density.
 Setting `conf_level=missing` removes the markings for the highest density interval.
 
-!!! note
-    This functionality is implemented using [Makie recipes](https://makie.juliaplots.org/v0.15.0/recipes.html)
-    and thus there are also additional auto-generated methods for `ridgeplot` and `ridgeplot!` that may be useful
-    when constructing more complex figures.
+`attributes` are passed onto [`coefplot`](@ref), `band!` and `lines!`.
+
+The mutating methods return the original object.
+
+!!! note 
+    Inestimable coefficients (coefficients removed by pivoting in the rank deficient case) 
+    are excluded.
 """
-function ridgeplot(x::MixedModelBootstrap;
-                   conf_level=0.95,
-                   vline_at_zero=true,
-                   show_intercept=true,
-                   attributes...)
+function ridgeplot(x::MixedModelBootstrap; show_intercept=true, kwargs...)
     # need to guarantee a min height of 200
     fig = Figure(; size=(640, max(200, 100 * _npreds(x; show_intercept))))
-    ax = Axis(fig[1, 1])
-    if !ismissing(conf_level)
-        pl = coefplot!(ax, x; conf_level, vline_at_zero, show_intercept, color=:black,
-                       attributes...)
-    end
-    pl = ridgeplot!(ax, x; vline_at_zero, conf_level, show_intercept, attributes...)
-    return Makie.FigureAxisPlot(fig, ax, pl)
+    return ridgeplot!(fig, x; show_intercept, kwargs...)
 end
 
-function Makie.plot!(ax::Axis, P::Type{<:RidgePlot}, allattrs::Makie.Attributes, x)
-    plot = Makie.plot!(ax.scene, P, allattrs, x)
+"""$(@doc ridgeplot)"""
+function ridgeplot!(fig::Indexable, x::MixedModelBootstrap; kwargs...)
+    ax = Axis(fig[1, 1])
+    ridgeplot!(ax, x; kwargs...)
+    return fig
+end
 
-    if haskey(allattrs, :title)
-        ax.title = allattrs.title[]
-    end
-    if haskey(allattrs, :xlabel)
-        ax.xlabel = allattrs.xlabel[]
+"""
+    _color(s::Symbol)
+    _color(p::Pair)
+    
+Extract the color part out of either a color name or a `(color, alpha)` pair.
+"""
+_color(s) = s
+_color(p::Pair) = first(p)
+
+"""$(@doc ridgeplot)"""
+function ridgeplot!(ax::Axis, x::MixedModelBootstrap;
+                    conf_level=0.95,
+                    vline_at_zero=true,
+                    show_intercept=true,
+                    attributes...)
+    xlabel = if !ismissing(conf_level)
+        @sprintf "Normalized bootstrap density and %g%% confidence interval" (conf_level *
+                                                                              100)
     else
-        lab = if !ismissing(allattrs.conf_level[])
-            @sprintf "Normalized bootstrap density and %g%% confidence interval" (allattrs.conf_level[] *
-                                                                                  100)
-        else
-            "Normalized bootstrap density"
-        end
-        ax.xlabel = lab
-    end
-    if haskey(allattrs, :ylabel)
-        ax.ylabel = allattrs.ylabel[]
+        "Normalized bootstrap density"
     end
-    reset_limits!(ax)
-    show_intercept = allattrs.show_intercept[]
 
-    # check conf_level so that we don't double print
-    # if coefplot took care of it for us
-    if ismissing(allattrs.conf_level[])
-        cn = _coefnames(x; show_intercept)
-        nticks = _npreds(x; show_intercept)
-        ax.yticks = (nticks:-1:1, cn)
-        ylims!(ax, 0, nticks + 1)
-        allattrs.vline_at_zero[] && vlines!(ax, 0; color=(:black, 0.75), linestyle=:dash)
+    if !ismissing(conf_level)
+        coefplot!(ax, x; conf_level, vline_at_zero, show_intercept, color=:black,
+                  attributes...)
     end
-    return plot
-end
 
-function Makie.plot!(plot::RidgePlot{<:Tuple{MixedModelBootstrap}})
-    boot, conf_level = plot[1][], plot.conf_level[]
-    df = transform!(DataFrame(boot.β), :coefname => ByRow(string) => :coefname)
-    plot.show_intercept[] || filter!(:coefname => !=("(Intercept)"), df)
+    attributes = merge((; xlabel, color=:black), attributes)
+    band_attributes = merge(attributes, (; color=(_color(attributes.color), 0.3)))
+
+    ax.xlabel = attributes.xlabel
+
+    df = transform!(DataFrame(x.β), :coefname => ByRow(string) => :coefname)
+    filter!(:coefname => in(_coefnames(x; show_intercept)), df)
     group = :coefname
     densvar = :β
     gdf = groupby(df, group)
 
-    y = length(gdf):-1:1
-
     dens = combine(gdf, densvar => kde => :kde)
 
     for (offset, row) in enumerate(reverse(eachrow(dens)))
         # multiply by 0.95 so that the ridges don't overlap
         dd = 0.95 * row.kde.density ./ maximum(row.kde.density)
-        lower = Observable(Point2f.(row.kde.x, offset))
-        upper = Observable(Point2f.(row.kde.x, dd .+ offset))
-        band!(plot, lower, upper; color=(:black, 0.3))
-        lines!(plot, upper; color=(:black, 1.0))
+        lower = Point2f.(row.kde.x, offset)
+        upper = Point2f.(row.kde.x, dd .+ offset)
+        band!(ax, lower, upper; band_attributes...)
+        lines!(ax, upper; attributes...)
+    end
+
+    # check conf_level so that we don't double print
+    # if coefplot took care of it for us
+    if ismissing(conf_level)
+        cn = _coefnames(x; show_intercept)
+        nticks = _npreds(x; show_intercept)
+        ax.yticks = (nticks:-1:1, cn)
+        ylims!(ax, 0, nticks + 1)
+        vline_at_zero && vlines!(ax, 0; color=(:black, 0.75), linestyle=:dash)
     end
 
-    return plot
+    reset_limits!(ax)
+
+    return ax
 end
 
 # """
diff --git a/src/ridge2d.jl b/src/ridge2d.jl
index cc15b98..14672c1 100644
--- a/src/ridge2d.jl
+++ b/src/ridge2d.jl
@@ -1,3 +1,19 @@
+"""
+    ridge2d(bs::MixedModelBootstrap; ptype=:β, kwargs...)
+    ridge2d!(f::$(Indexable), bs::MixedModelBootstrap; ptype=:β)
+
+Plot pairwise bivariate scatter plots with overlain densities for a bootstrap sample.
+
+`ptype` specifies the set of parameters to examine, e.g. `:β`, `:σ`, `:ρ`.
+
+The mutating methods return the original object.
+"""
+function ridge2d(bs::MixedModelBootstrap, args...; kwargs...)
+    f = Figure(; size=(1000, 1000)) # use an aspect ratio of 1 for the whole figure
+
+    return ridge2d!(f, bs, args...; kwargs...)
+end
+
 function _ridge2d_panel!(ax::Axis, i::Int, j::Int, cnames::Vector{Symbol}, tbl)
     x = Tables.getcolumn(tbl, cnames[j])
     y = Tables.getcolumn(tbl, cnames[i])
@@ -10,17 +26,11 @@ function _ridge2d_panel!(ax::Axis, i::Int, j::Int, cnames::Vector{Symbol}, tbl)
     return plt
 end
 
-"""
-    ridge2d!(f::Union{Makie.FigureLike,Makie.GridLayout}, bs::MixedModelBootstrap; 
-             ptype=:β)
-
-Plot pairwise bivariate scatter plots with overlain densities for a bootstrap sample.
+# No Axis variant here because we always need to great a subgrid
+# we don't yet expose any further configuration options / attributes
 
-
-`ptype` specifies the set of parameters to examine, e.g. `:β`, `:σ`, `:ρ`.
-"""
-function ridge2d!(f::Union{Makie.FigureLike,Makie.GridLayout}, bs::MixedModelBootstrap;
-                  ptype=:β)
+"""$(@doc ridge2d)"""
+function ridge2d!(f::Indexable, bs::MixedModelBootstrap; ptype=:β)
     tbl = bs.tbl
     cnames = [string(x) for x in propertynames(tbl)[2:end]]
     filter!(startswith(string(ptype)), cnames)
@@ -31,10 +41,3 @@ function ridge2d!(f::Union{Makie.FigureLike,Makie.GridLayout}, bs::MixedModelBoo
     splomaxes!(f, cnames, _ridge2d_panel!, Symbol.(cnames), tbl)
     return f
 end
-
-"""$(@doc ridge2d!)"""
-function ridge2d(bs::MixedModelBootstrap, args...; kwargs...)
-    f = Figure(; size=(1000, 1000)) # use an aspect ratio of 1 for the whole figure
-
-    return ridge2d!(f, bs, args...; kwargs...)
-end
diff --git a/src/utilities.jl b/src/utilities.jl
index 8ddd398..f532d12 100644
--- a/src/utilities.jl
+++ b/src/utilities.jl
@@ -1,16 +1,16 @@
 function _coefnames(x; show_intercept=true)
-    cn = coefnames(x)
+    cn = fixefnames(x)
     return show_intercept ? cn : filter!(!=("(Intercept)"), cn)
 end
 
 function _coefnames(x::MixedModelBootstrap; show_intercept=true)
-    cn = collect(string.(propertynames(first(x.fits).β)))
+    cn = [string(k) for (k, v) in pairs(first(x.fits).β) if !isequal(v, -0.0)]
     return show_intercept ? cn : filter!(!=("(Intercept)"), cn)
 end
 
 """
-    confint_table(x::StatsBase.StatisticalModel, level=0.95)
-    confint_table(x::MixedModelBootstrap, level=0.95)
+    confint_table(x::MixedModel, level=0.95; show_intercept=true)
+    confint_table(x::MixedModelBootstrap, level=0.95; show_intercept=true)
 
 Return a DataFrame of coefficient names, point estimates and confidence intervals.
 
@@ -26,26 +26,33 @@ The returned table has the following columns:
 - `lower`: the lower edge of the confidence interval
 - `upper`: the upper edge of the confidence interval
 
+!!! note
+    This function is internal and may be removed in a future release
+    without being considered a breaking change.
 """
-function confint_table(x::StatsBase.StatisticalModel, level=0.95)
+function confint_table(x::MixedModel, level=0.95; show_intercept=true)
     # taking from the lower tail
     semultiple = zquantile((1 - level) / 2)
     se = stderror(x)
+    est = coef(x)
 
-    return DataFrame(;
-                     coefname=coefnames(x),
-                     estimate=coef(x),
-                     lower=coef(x) + semultiple * se,
-                     upper=coef(x) - semultiple * se)
+    df = DataFrame(;
+                   coefname=coefnames(x),
+                   estimate=coef(x),
+                   # signs are 'swapped' b/c semultiple comes from the lower tail
+                   lower=est + semultiple * se,
+                   upper=est - semultiple * se)
+    return filter!(:coefname => in(_coefnames(x; show_intercept)), df)
 end
 
-function confint_table(x::MixedModelBootstrap, level=0.95)
+function confint_table(x::MixedModelBootstrap, level=0.95; show_intercept=true)
     df = transform!(select!(DataFrame(x.β), Not(:iter)),
                     :coefname => ByRow(string) => :coefname)
     ci(x) = shortestcovint(x, level)
-    return combine(groupby(df, :coefname),
-                   :β => mean => :estimate,
-                   :β => NamedTuple{(:lower, :upper)} ∘ ci => [:lower, :upper])
+    df = combine(groupby(df, :coefname),
+                 :β => mean => :estimate,
+                 :β => NamedTuple{(:lower, :upper)} ∘ ci => [:lower, :upper])
+    return filter!(:coefname => in(_coefnames(x; show_intercept)), df)
 end
 
 _npreds(x; show_intercept=true) = length(_coefnames(x; show_intercept))
diff --git a/test/Project.toml b/test/Project.toml
index cfdfe2a..0400cfa 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -6,9 +6,11 @@ Makie = "ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a"
 MixedModels = "ff71e718-51f3-5ec2-a782-8ffcbfa3c316"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
+Suppressor = "fd094767-a336-5f1f-9728-57cf17d0bbfb"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 TestSetExtensions = "98d24dd4-01ad-11ea-1b02-c9a08f80db04"
 
 [compat]
 Aqua = "0.5, 0.6"
+Suppressor = "0.2"
 TestSetExtensions = "3"
diff --git a/test/clevelandaxes.jl b/test/clevelandaxes.jl
index 56a1885..0fd1079 100644
--- a/test/clevelandaxes.jl
+++ b/test/clevelandaxes.jl
@@ -17,6 +17,7 @@ catch err
     end
 end
 for i in 1:4, j in 1:4
+    local x, y
     x = randn(MersenneTwister(i), n)
     y = randn(MersenneTwister(j), n)
     scatter!(f[i, j], x, y)
diff --git a/test/coefplot.jl b/test/coefplot.jl
index 273f1e2..6f5aac6 100644
--- a/test/coefplot.jl
+++ b/test/coefplot.jl
@@ -3,3 +3,9 @@ f = coefplot(m1)
 
 f = coefplot(b1)
 @test save(joinpath(OUTDIR, "coef_sleepstudy_boot.png"), f)
+
+f = coefplot(mr)
+@test save(joinpath(OUTDIR, "coef_rankdeficient.png"), f)
+
+f = coefplot(br)
+@test save(joinpath(OUTDIR, "coef_rankdeficient_boot.png"), f)
diff --git a/test/ridgeplot.jl b/test/ridgeplot.jl
index 5cc611a..edc5feb 100644
--- a/test/ridgeplot.jl
+++ b/test/ridgeplot.jl
@@ -1,2 +1,5 @@
 f = ridgeplot(b1)
 @test save(joinpath(OUTDIR, "ridge_sleepstudy.png"), f)
+
+f = ridgeplot(br)
+@test save(joinpath(OUTDIR, "ridge_rankdeficient.png"), f)
diff --git a/test/runtests.jl b/test/runtests.jl
index 99c45c6..6831c67 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -5,6 +5,7 @@ using MixedModels
 using MixedModelsMakie
 using Random # we don't depend on exact PRNG vals, so no need for StableRNGs
 using Statistics
+using Suppressor
 using Test
 using TestSetExtensions
 
@@ -41,6 +42,13 @@ g1 = fit(MixedModel,
          MixedModels.dataset(:verbagg),
          Bernoulli(); progress)
 
+rng = MersenneTwister(0)
+x = rand(rng, 100)
+data = (x=x, x2=1.5 .* x, y=rand(rng, [0, 1], 100), z=repeat('A':'T', 5))
+mr = @suppress fit(MixedModel, @formula(y ~ x + x2 + (1 | z)), data; progress)
+br = parametricbootstrap(MersenneTwister(42), 500, mr; progress,
+                         optsum_overrides=(; ftol_rel=1e-6))
+
 @testset ExtendedTestSet "MixedModelsMakie.jl" begin
     @testset "Aqua" begin
         # we can't check for unbound type parameters