diff --git a/routers/repo/compare.go b/routers/repo/compare.go
index 203b740082d0..d23bccd09ad0 100644
--- a/routers/repo/compare.go
+++ b/routers/repo/compare.go
@@ -433,6 +433,7 @@ func CompareDiff(ctx *context.Context) {
 	ctx.Data["IsDiffCompare"] = true
 	ctx.Data["RequireHighlightJS"] = true
 	ctx.Data["RequireTribute"] = true
+	ctx.Data["RequireSimpleMDE"] = true
 	ctx.Data["PullRequestWorkInProgressPrefixes"] = setting.Repository.PullRequest.WorkInProgressPrefixes
 	setTemplateIfExists(ctx, pullRequestTemplateKey, pullRequestTemplateCandidates)
 	renderAttachmentSettings(ctx)