diff --git a/src/page-components/scheme/m3-dynamic-scheme/Builder.tsx b/src/page-components/scheme/m3-dynamic-scheme/Builder.tsx
index 5ea4c39..e1bb953 100644
--- a/src/page-components/scheme/m3-dynamic-scheme/Builder.tsx
+++ b/src/page-components/scheme/m3-dynamic-scheme/Builder.tsx
@@ -99,15 +99,13 @@ export function M3DynamicSchemeBuilder({ scheme, onBuildCompleted }: M3DynamicSc
     (_state, formData) => {
       const errMsg = new Map<string, string>();
 
-      const sourceColor = formData.get('source') as string;
-      if (isNil(sourceColor) || isEmpty(sourceColor)) {
+      const collectedSource = collectSchemeSource(formData);
+      if (isNil(collectedSource.source) || isEmpty(collectedSource.source)) {
         errMsg.set('source', 'Source color is required');
       }
       if (!isEmpty(errMsg)) return errMsg;
 
       try {
-        const collectedSource = collectSchemeSource(formData);
-
         const generate_scheme = colorFn.generate_material_design_3_dynamic_scheme(
           collectedSource.source,
           collectedSource.error,