diff --git a/packages/core/src/server/packets/decorators/action.js b/packages/core/src/server/packets/decorators/action.js
index 56a017d..4acc446 100644
--- a/packages/core/src/server/packets/decorators/action.js
+++ b/packages/core/src/server/packets/decorators/action.js
@@ -26,10 +26,10 @@ export default (Action, flecks) => class ProjectAction extends Action {
         const buffer = await readFile(path);
         const json = fromBuffer(buffer, flecks);
         if (json.history?.redo?.length) {
-          const patch = json.history.redo[json.history.redo.length - 1];
+          const {group, patch} = json.history.redo.at(-1);
           socket.send(['Action', patchJsonResource({patch, project, uri}, true)]);
           applyPatch(json, patch);
-          json.history.undo.push(compare(json, fromBuffer(buffer, flecks)));
+          json.history.undo.push({group, patch: compare(json, fromBuffer(buffer, flecks))});
           json.history.redo.pop();
           await writeFile(path, toBuffer(json, flecks));
         }
@@ -47,10 +47,10 @@ export default (Action, flecks) => class ProjectAction extends Action {
         const buffer = await readFile(path);
         const json = fromBuffer(buffer, flecks);
         if (json.history?.undo?.length) {
-          const patch = json.history.undo[json.history.undo.length - 1];
+          const {group, patch} = json.history.undo.at(-1);
           socket.send(['Action', patchJsonResource({patch, project, uri}, true)]);
           applyPatch(json, patch);
-          json.history.redo.push(compare(json, fromBuffer(buffer, flecks)));
+          json.history.redo.push({group, patch: compare(json, fromBuffer(buffer, flecks))});
           json.history.undo.pop();
           await writeFile(path, toBuffer(json, flecks));
         }
diff --git a/packages/core/src/server/start-flush.js b/packages/core/src/server/start-flush.js
index 528beda..260e125 100644
--- a/packages/core/src/server/start-flush.js
+++ b/packages/core/src/server/start-flush.js
@@ -7,39 +7,37 @@ const startFlush = (flecks) => {
   const flushPatches = async () => {
     const patches = flecks.get('$persea/core.patches');
     if (patches.length > 0) {
-      const patching = {};
       while (patches.length > 0) {
-        const {patch, project, uri} = patches.shift();
+        const {
+          group,
+          patch,
+          project,
+          uri,
+        } = patches.shift();
         const path = join(process.cwd(), 'projects', project, uri);
-        if (!patching[path]) {
-          const {toBuffer, fromBuffer} = flecks.get('$avocado/resource/persea.controllers')
-            .find(({matcher}) => uri.match(matcher));
-          patching[path] = new Promise((resolve) => {
-            readFile(path).then((buffer) => {
-              resolve({
-                fromBuffer,
-                toBuffer,
-                json: fromBuffer(buffer, flecks),
-              });
-            });
-          });
-        }
+        // Get controller.
+        const {toBuffer, fromBuffer} = flecks.get('$avocado/resource/persea.controllers')
+          .find(({matcher}) => uri.match(matcher));
+        // Load.
         // eslint-disable-next-line no-await-in-loop
-        const {json} = await patching[path];
+        const buffer = await readFile(path);
+        const json = fromBuffer(buffer, flecks);
+        // Patch.
         applyPatch(json, patch);
+        // Manage history.
+        const undo = compare(json, fromBuffer(buffer, flecks));
+        json.history = json.history || {redo: [], undo: []};
+        json.history.redo = [];
+        if (
+          0 === json.history.undo.length
+          || group !== json.history.undo.at(-1).group
+        ) {
+          json.history.undo.push({group, patch: undo});
+        }
+        // Flush.
+        // eslint-disable-next-line no-await-in-loop
+        await writeFile(path, toBuffer(json, flecks));
       }
-      await Promise.all(
-        Object.entries(patching)
-          .map(async ([path, promise]) => {
-            const {fromBuffer, toBuffer, json} = await promise;
-            const buffer = await readFile(path);
-            const undo = compare(json, fromBuffer(buffer, flecks));
-            json.history = json.history || {redo: [], undo: []};
-            json.history.redo = [];
-            json.history.undo.push(undo);
-            return writeFile(path, toBuffer(json, flecks));
-          }),
-      );
     }
     setTimeout(flushPatches, 0);
   };