diff --git a/css/mathfield.less b/css/mathfield.less
index dd56bcd8b..c46ee61a8 100644
--- a/css/mathfield.less
+++ b/css/mathfield.less
@@ -430,12 +430,12 @@ menu .ML__base {
   font-size: 21px;
   // color: transparent;
   border: none;
-  border-radius: 2px;
-  line-height: 1;
+  border-radius: 0;
+  line-height: 21px;
   text-align: center;
-  padding: 4px;
+  padding: 0;
   margin: 0;
-}
+  }
 
 .menu-container-border [part=menu-item] {
   font-size: 2rem;
diff --git a/src/editor/default-menu.ts b/src/editor/default-menu.ts
index dd9fb0b92..0e60951eb 100644
--- a/src/editor/default-menu.ts
+++ b/src/editor/default-menu.ts
@@ -11,6 +11,7 @@ import { Atom } from 'core/atom-class';
 import { VARIANT_REPERTOIRE } from 'core/modes-math';
 import { contrast } from 'ui/colors/utils';
 import { _Mathfield } from 'editor-mathfield/mathfield-private';
+import { _MenuItemState } from 'ui/menu/menu-item';
 
 // Return a string from the selection, if all the atoms are character boxes
 // (i.e. not fractions, square roots, etc...)
@@ -242,24 +243,53 @@ function getColorSubmenu(mf: _Mathfield): MenuItem[] {
   return result;
 }
 
+class InsertMatrixMenuItem extends _MenuItemState<{
+  row: number;
+  col: number;
+}> {
+  row: number;
+  col: number;
+  constructor(decl, parent, row, col) {
+    super(decl, parent);
+    this.row = row;
+    this.col = col;
+  }
+
+  set active(value: boolean) {
+    const cells = this.parentMenu.children as InsertMatrixMenuItem[];
+    if (value) {
+      // Make all the items with a smaller column or row active as well
+      for (const cell of cells) {
+        cell.element.classList.toggle(
+          'active',
+          cell.row <= this.row && cell.col <= this.col
+        );
+      }
+    } else for (const cell of cells) cell.element.classList.remove('active');
+  }
+}
+
 function getInsertMatrixSubmenu(mf: _Mathfield): MenuItem[] {
   const result: MenuItem[] = [];
 
-  for (let rows = 1; rows <= 5; rows++) {
-    for (let cols = 1; cols <= 5; cols++) {
+  for (let row = 1; row <= 5; row++) {
+    for (let col = 1; col <= 5; col++) {
       result.push({
+        createMenuItem: (decl, parent) =>
+          new InsertMatrixMenuItem(decl, parent, row, col),
         label: `☐`,
+        data: { row, col },
         onMenuSelect: () => {
           mf.insert(
-            `\\begin{pmatrix}${Array(cols)
-              .fill(Array(rows).fill('#?').join(' & '))
+            `\\begin{pmatrix}${Array(col)
+              .fill(Array(row).fill('#?').join(' & '))
               .join('\\\\')}\\end{pmatrix}`,
             {
               selectionMode: 'item',
             }
           );
         },
-      });
+      } as MenuItem);
     }
   }
 
diff --git a/src/public/ui-menu-types.ts b/src/public/ui-menu-types.ts
index 2778d683c..2496bfcdc 100644
--- a/src/public/ui-menu-types.ts
+++ b/src/public/ui-menu-types.ts
@@ -133,7 +133,7 @@ export function isSubmenu(item: MenuItem): item is MenuItemSubmenu {
 export function isCommand<T>(item: MenuItem<T>): item is MenuItemCommand<T> {
   return (
     ('type' in item && item.type === 'command') ||
-    'onSelect' in item ||
+    'onMenuSelect' in item ||
     'id' in item
   );
 }
diff --git a/src/ui/menu/menu-item.ts b/src/ui/menu/menu-item.ts
index bce30541e..ddddc50da 100644
--- a/src/ui/menu/menu-item.ts
+++ b/src/ui/menu/menu-item.ts
@@ -157,8 +157,7 @@ export class _MenuItemState<T> implements MenuItemState<T> {
   set active(value: boolean) {
     if (!this.element) return;
     // The active state is immediate, no need to dirty it
-    if (value) this.element.classList.add('active');
-    else this.element.classList.remove('active');
+    this.element.classList.toggle('active', value);
   }
 
   get items(): MenuItemState[] | undefined {
diff --git a/src/ui/menu/menu-list.ts b/src/ui/menu/menu-list.ts
index b3ca7125f..66016e650 100644
--- a/src/ui/menu/menu-list.ts
+++ b/src/ui/menu/menu-list.ts
@@ -44,6 +44,10 @@ export class _MenuListState implements MenuListState {
     this.menuItems = items;
   }
 
+  get children(): MenuItemState[] {
+    return this._menuItems;
+  }
+
   /** Setting the menu items will reset this item and
    * redefine a set of _MenuItem objects
    */
@@ -54,8 +58,12 @@ export class _MenuListState implements MenuListState {
     this.parentMenu = parent;
     items = [...items];
 
-    // Create the _MenuItem objects
-    this._menuItems = items.map((x) => new _MenuItemState(x, this));
+    // Create the _MenuItemState objects
+    this._menuItems = items.map((x) =>
+      x['createMenuItem']
+        ? x['createMenuItem'](x, this)
+        : new _MenuItemState(x, this)
+    );
 
     this.hasCheck = undefined;
   }
diff --git a/src/ui/menu/private-types.ts b/src/ui/menu/private-types.ts
index e580f98de..139927ca4 100644
--- a/src/ui/menu/private-types.ts
+++ b/src/ui/menu/private-types.ts
@@ -50,9 +50,11 @@ export interface MenuItemState<T = unknown> {
 
 /** @internal */
 export interface MenuListState {
-  readonly parentMenu: MenuListState | null;
   readonly rootMenu: RootMenuState;
 
+  readonly parentMenu: MenuListState | null;
+  readonly children: MenuItemState[];
+
   readonly element: HTMLElement | null;
   isSubmenuOpen: boolean;