diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 67f33f6..a5c735a 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -20,6 +20,9 @@ jobs:
           - os: windows-latest
             name: Windows Vulkan
             build_flags: "-d:useVulkan"
+          - os: windows-latest
+            name: Windows CPU
+            build_flags: "-d:useCpu"
           - os: ubuntu-latest
             name: Linux OpenGL
             build_flags: ""
@@ -59,6 +62,7 @@ jobs:
           nim r -d:silkyTesting tests/test_layout.nim
           nim r -d:silkyTesting tests/test_layout_regressions.nim
           nim r ${{ matrix.build_flags }} tests/test_layout_clips.nim
+          nim r ${{ matrix.build_flags }} tests/test_cpu_backend.nim
 
       - name: Compile examples
         if: ${{ !matrix.emscripten }}
diff --git a/nimby.lock b/nimby.lock
index 2ccf14d..fea1329 100644
--- a/nimby.lock
+++ b/nimby.lock
@@ -8,7 +8,7 @@ nimsimd 1.3.2 https://github.com/guzba/nimsimd 3f6b2668ffb0867d0bf786a658b817763
 bumpy 1.1.3 https://github.com/treeform/bumpy dc9a3d6d15680ec7f603959d65ba8ee4f1ddbc72
 crunchy 0.1.11 https://github.com/guzba/crunchy 98eb6526982bb8aae8eec6e8781f4539fa19e049
 bitty 0.1.4 https://github.com/treeform/bitty/ c40e81277c04befa37234cba5052f58648bef895
-windy 0.4.4 https://github.com/treeform/windy 4221e9b19b701986889134fea963c6b0191186a7
+windy 0.5.0 https://github.com/treeform/windy 5971abb08f416cfb8a3603a3093503eb07f2f5c4
 opengl 1.2.9 https://github.com/nim-lang/opengl 8e2e098f82dc5eefd874488c37b5830233cd18f4
 urlly 1.1.1 https://github.com/treeform/urlly 99784779f05649df25fd9c33003d8ef6de027345
 ws 0.5.0 https://github.com/treeform/ws cbb8f763b436669392d10baec2a45778395395cc
diff --git a/src/silky.nim b/src/silky.nim
index 7349d69..64b0ec8 100644
--- a/src/silky.nim
+++ b/src/silky.nim
@@ -23,8 +23,3 @@ else:
   export widgets except
     button, checkBox, clickableIcon, dropDown, frame, group, h1text, icon,
     iconButton, image, listBox, progressBar, radioButton, ribbon, scrubber, text
-
-  when defined(useMetal4) or defined(useCpu):
-    proc loadExtensions*() {.inline.} =
-      ## No-op helper for non-OpenGL backends.
-      discard