--- a/gfx/thebes/gfxPrefs.h
+++ b/gfx/thebes/gfxPrefs.h
@@ -423,17 +423,17 @@ private:
   DECL_GFX_PREF(Live, "test.mousescroll",                      MouseScrollTestingEnabled, bool, false);
 
   DECL_GFX_PREF(Live, "ui.click_hold_context_menus.delay",     UiClickHoldContextMenusDelay, int32_t, 500);
 
   // WebGL (for pref access from Worker threads)
   DECL_GFX_PREF(Live, "webgl.all-angle-options",               WebGLAllANGLEOptions, bool, false);
   DECL_GFX_PREF(Live, "webgl.angle.force-d3d11",               WebGLANGLEForceD3D11, bool, false);
   DECL_GFX_PREF(Live, "webgl.angle.try-d3d11",                 WebGLANGLETryD3D11, bool, false);
-  DECL_GFX_PREF(Once, "webgl.angle.force-warp",                WebGLANGLEForceWARP, bool, false);
+  DECL_GFX_PREF(Live, "webgl.angle.force-warp",                WebGLANGLEForceWARP, bool, false);
   DECL_GFX_PREF(Live, "webgl.bypass-shader-validation",        WebGLBypassShaderValidator, bool, true);
   DECL_GFX_PREF(Live, "webgl.can-lose-context-in-foreground",  WebGLCanLoseContextInForeground, bool, true);
   DECL_GFX_PREF(Live, "webgl.default-no-alpha",                WebGLDefaultNoAlpha, bool, false);
   DECL_GFX_PREF(Live, "webgl.disable-angle",                   WebGLDisableANGLE, bool, false);
   DECL_GFX_PREF(Live, "webgl.disable-extensions",              WebGLDisableExtensions, bool, false);
   DECL_GFX_PREF(Live, "webgl.dxgl.enabled",                    WebGLDXGLEnabled, bool, false);
   DECL_GFX_PREF(Live, "webgl.dxgl.needs-finish",               WebGLDXGLNeedsFinish, bool, false);