diff --git a/templates/repo/diff/comment_form.tmpl b/templates/repo/diff/comment_form.tmpl
index 109f167967..8565deb168 100644
--- a/templates/repo/diff/comment_form.tmpl
+++ b/templates/repo/diff/comment_form.tmpl
@@ -17,6 +17,7 @@
 			"TextareaName" "content"
 			"TextareaPlaceholder" ($.locale.Tr "repo.diff.comment.placeholder")
 			"DropzoneParentContainer" "form"
+			"DisableAutosize" "true"
 		)}}
 
 		<div class="field footer gt-mx-3">
diff --git a/templates/shared/combomarkdowneditor.tmpl b/templates/shared/combomarkdowneditor.tmpl
index 4c1742d21f..9715d0ef01 100644
--- a/templates/shared/combomarkdowneditor.tmpl
+++ b/templates/shared/combomarkdowneditor.tmpl
@@ -10,6 +10,7 @@ Template Attributes:
 * TextareaPlaceholder: placeholder attribute for the textarea
 * TextareaAriaLabel: aria-label attribute for the textarea
 * DropzoneParentContainer: container for file upload (leave it empty if no upload)
+* DisableAutosize: whether to disable automatic height resizing
 */}}
 <div {{if .ContainerId}}id="{{.ContainerId}}"{{end}} class="combo-markdown-editor {{.ContainerClasses}}" data-dropzone-parent-container="{{.DropzoneParentContainer}}">
 	{{if .MarkdownPreviewUrl}}
@@ -45,7 +46,7 @@ Template Attributes:
 			</div>
 		</markdown-toolbar>
 		<text-expander keys=": @" suffix="">
-			<textarea class="markdown-text-editor js-quick-submit"{{if .TextareaName}} name="{{.TextareaName}}"{{end}}{{if .TextareaPlaceholder}} placeholder="{{.TextareaPlaceholder}}"{{end}}{{if .TextareaAriaLabel}} aria-label="{{.TextareaAriaLabel}}"{{end}}>{{.TextareaContent}}</textarea>
+			<textarea class="markdown-text-editor js-quick-submit"{{if .TextareaName}} name="{{.TextareaName}}"{{end}}{{if .TextareaPlaceholder}} placeholder="{{.TextareaPlaceholder}}"{{end}}{{if .TextareaAriaLabel}} aria-label="{{.TextareaAriaLabel}}"{{end}}{{if .DisableAutosize}} data-disable-autosize="{{.DisableAutosize}}"{{end}}>{{.TextareaContent}}</textarea>
 		</text-expander>
 		<script>
 			if (localStorage?.getItem('markdown-editor-monospace') === 'true') {
diff --git a/web_src/js/features/comp/ComboMarkdownEditor.js b/web_src/js/features/comp/ComboMarkdownEditor.js
index 3d696be75b..d61b6b43cc 100644
--- a/web_src/js/features/comp/ComboMarkdownEditor.js
+++ b/web_src/js/features/comp/ComboMarkdownEditor.js
@@ -69,7 +69,10 @@ class ComboMarkdownEditor {
     this.textarea.id = `_combo_markdown_editor_${String(elementIdCounter++)}`;
     this.textarea.addEventListener('input', (e) => this.options?.onContentChanged?.(this, e));
     this.applyEditorHeights(this.textarea, this.options.editorHeights);
-    this.textareaAutosize = autosize(this.textarea, {viewportMarginBottom: 130});
+
+    if (this.textarea.getAttribute('data-disable-autosize') !== 'true') {
+      this.textareaAutosize = autosize(this.textarea, {viewportMarginBottom: 130});
+    }
 
     this.textareaMarkdownToolbar = this.container.querySelector('markdown-toolbar');
     this.textareaMarkdownToolbar.setAttribute('for', this.textarea.id);
@@ -247,7 +250,7 @@ class ComboMarkdownEditor {
     } else {
       this.textarea.value = v;
     }
-    this.textareaAutosize.resizeToFit();
+    this.textareaAutosize?.resizeToFit();
   }
 
   focus() {