diff --git a/app/src/protyle/toolbar/index.ts b/app/src/protyle/toolbar/index.ts
index 0d0f8fec2..6efce2cd1 100644
--- a/app/src/protyle/toolbar/index.ts
+++ b/app/src/protyle/toolbar/index.ts
@@ -891,9 +891,8 @@ export class Toolbar {
                     focusSideBlock(renderElement);
                 }
             } else if (event.key === "Tab") {
-                const start = textElement.selectionStart;
-                textElement.value = textElement.value.substring(0, start) + "\t" + textElement.value.substring(textElement.selectionEnd);
-                textElement.selectionStart = textElement.selectionEnd = start + 1;
+                // https://github.com/siyuan-note/siyuan/issues/5270
+                document.execCommand("insertText", false, "\t");
                 event.preventDefault();
             }
         });
diff --git a/app/src/protyle/wysiwyg/input.ts b/app/src/protyle/wysiwyg/input.ts
index 7819b6e83..7b8c11201 100644
--- a/app/src/protyle/wysiwyg/input.ts
+++ b/app/src/protyle/wysiwyg/input.ts
@@ -181,6 +181,8 @@ export const input = async (protyle: IProtyle, blockElement: HTMLElement, range:
         protyle.hint.render(protyle);
     }
     hideElements(["gutter"], protyle);
+    // 在数学公式输入框中撤销到最后一步，再继续撤销会撤销编辑器正文内容，从而出发 input 事件
+    protyle.toolbar.subElement.classList.add("fn__none");
     updateInput(html, protyle, id, type, todoOldHTML);
 };