Do not clear headers when switching between tabs

Author: klippx

packages/graphiql-react/src/editor/tabs.ts

@@ -278,7 +278,7 @@ export function useSetEditorValues({
     }) => {
       queryEditor?.setValue(query ?? '');
       variableEditor?.setValue(variables ?? '');
-      headerEditor?.setValue(headers ?? '');
+      headerEditor?.setValue(headers ?? headerEditor?.getValue() ?? '');
       responseEditor?.setValue(response ?? '');
     },
     [headerEditor, queryEditor, responseEditor, variableEditor],