diff --git a/apps/web/components/editors/tiptap/tiptap-mermaid-extension.ts b/apps/web/components/editors/tiptap/tiptap-mermaid-extension.ts
index 53279adcfc..ba7c77c9b8 100644
--- a/apps/web/components/editors/tiptap/tiptap-mermaid-extension.ts
+++ b/apps/web/components/editors/tiptap/tiptap-mermaid-extension.ts
@@ -50,7 +50,7 @@ const MERMAID_KEYWORDS = [
   "zenuml",
 ];
 
-const MERMAID_RE = new RegExp(`^\\s*(?:${MERMAID_KEYWORDS.join("|")})(?:\\s|$)`, "m");
+const MERMAID_RE = new RegExp(`^\\s*(?:${MERMAID_KEYWORDS.join("|")})(?:\\s|$)`);
 
 /** Detect mermaid content by language tag OR by first-line keyword. */
 export function isMermaidContent(language: string | null | undefined, text: string): boolean {