diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5c67fbd..0727b18 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -40,8 +40,8 @@ jobs:
         continue-on-error: true
       - name: Install carge llvm-cov
         run: cargo install cargo-llvm-cov
-      # - name: Install X components
-      #   run: sudo apt-get install -y libxinerama-dev libxcursor-dev libxfixes-dev libxft-dev libpango1.0-dev libpangoxft-1.0-0 libpangocairo-1.0-0
+      - name: Install X components
+        run: sudo apt-get install -y libxinerama-dev libxcursor-dev libxfixes-dev libxft-dev libpango1.0-dev libpangoxft-1.0-0 libpangocairo-1.0-0
       - name: Run Clippy
         run: cargo clippy --features ui,use_rayon
       - name: Run tests and coverage
@@ -50,7 +50,7 @@ jobs:
           export CARGO_TARGET_DIR=$CARGO_LLVM_COV_TARGET_DIR
           export CARGO_INCREMENTAL=1
           cargo llvm-cov clean --workspace
-          cargo test --features use_rayon # FIXME: ui
+          cargo test --features ui,use_rayon # FIXME: ui
           cargo llvm-cov --no-run --lcov --output-path coverage.lcov
       - uses: codecov/codecov-action@v3
         with:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9f7bf2d..f0f15d2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 - Add Python typing for FFS results.
 - Distinguish stored states and number of configurations for FFS surfaces.
 - Make FFS state references more useful.
+- Fix rayon use in Python (parallel execution).
 
 # 0.13.1
 
diff --git a/py-rgrow/Cargo.toml b/py-rgrow/Cargo.toml
index 637b19d..1a04aca 100644
--- a/py-rgrow/Cargo.toml
+++ b/py-rgrow/Cargo.toml
@@ -32,7 +32,7 @@ pyo3-polars = {workspace = true}
 
 [dependencies.rgrow]
 path = "../rgrow"
-features = ["python"]
+features = ["python", "use_rayon"]
 default-features = false
 
 [dependencies.pyo3]
diff --git a/rgrow/Cargo.toml b/rgrow/Cargo.toml
index 2ff746f..81d036b 100644
--- a/rgrow/Cargo.toml
+++ b/rgrow/Cargo.toml
@@ -36,7 +36,7 @@ name = "rgrow"
 path = "src/main.rs"
 
 [features]
-default = ["use_rayon"]
+default = ["use_rayon", "ui"]
 ui = ["fltk", "pixels"]
 use_rayon = ["rayon"]
 python = ["pyo3", "numpy"]
diff --git a/rgrow/src/ffs.rs b/rgrow/src/ffs.rs
index 3818657..24b9d8f 100644
--- a/rgrow/src/ffs.rs
+++ b/rgrow/src/ffs.rs
@@ -12,6 +12,7 @@ use crate::tileset::{CanvasType, FromTileSet, Model, TileSet, SIZE_DEFAULT};
 
 #[cfg(feature = "python")]
 use polars::prelude::*;
+#[cfg(feature = "python")]
 use python::PyState;
 
 use super::*;