diff --git a/editor/libeditor/html/nsHTMLCSSUtils.cpp b/editor/libeditor/html/nsHTMLCSSUtils.cpp
index c4a6567dfb3..f74213e2287 100644
--- a/editor/libeditor/html/nsHTMLCSSUtils.cpp
+++ b/editor/libeditor/html/nsHTMLCSSUtils.cpp
@@ -642,7 +642,6 @@ nsHTMLCSSUtils::GetComputedStyle(dom::Element* aElement)
   MOZ_ASSERT(aElement);
 
   nsIDocument* doc = aElement->GetCurrentDoc();
-  NS_ASSERTION(doc, "Trying to compute style of detached element");
   NS_ENSURE_TRUE(doc, nullptr);
 
   nsIPresShell* presShell = doc->GetShell();