diff --git a/src/chainedvector.jl b/src/chainedvector.jl
index 173aa77..bbe47b6 100644
--- a/src/chainedvector.jl
+++ b/src/chainedvector.jl
@@ -906,6 +906,7 @@ function Base.findall(A::ChainedVector{Bool})
 end
 
 Base.findall(f::Function, x::ChainedVector) = findall(map(f, x))
+Base.findall(f::Base.Fix2{typeof(in)}, x::ChainedVector) = findall(map(f, x))
 
 function Base.filter(f, a::ChainedVector{T}) where {T}
     j = 1
diff --git a/test/chainedvector.jl b/test/chainedvector.jl
index 5e7a464..a0e70ff 100644
--- a/test/chainedvector.jl
+++ b/test/chainedvector.jl
@@ -591,7 +591,7 @@ end
     @test reduce(vcat, cv_of_abstractvectors) isa Any
     @test_throws "reserved" Base.broadcasted(Base.Broadcast.ArrayStyle{Matrix}(), cv)
     @test copyto!(pda_1dim, cv) isa Any
-    @test_broken findall(fix2in, cv) isa Any
+    @test findall(fix2in, cv) isa Any
     # I think this should not be fixed by us as long as we don't import SparseArrays:
     @test_throws MethodError copyto!(sv, cv) isa Any
 end
\ No newline at end of file