--- a/toolkit/components/typeaheadfind/nsTypeAheadFind.cpp
+++ b/toolkit/components/typeaheadfind/nsTypeAheadFind.cpp
@@ -1263,19 +1263,19 @@ nsTypeAheadFind::IsRangeVisible(nsIPresS
   nsRectVisibility rectVisibility = nsRectVisibility_kAboveViewport;
 
   if (!aGetTopVisibleLeaf && !frame->GetRect().IsEmpty()) {
     rectVisibility =
       aPresShell->GetRectVisibility(frame,
                                     nsRect(nsPoint(0,0), frame->GetSize()),
                                     minDistance);
 
-    if (rectVisibility != nsRectVisibility_kAboveViewport) {
-      // This is an early exit case, where we return true iff the range
-      // is actually rendered.
+    if (rectVisibility == nsRectVisibility_kVisible) {
+      // This is an early exit case, where we return true if and only if
+      // the range is actually rendered.
       return IsRangeRendered(aPresShell, aPresContext, aRange);
     }
   }
 
   // Below this point, we know the range is not in the viewport.
 
   if (!aMustBeInViewPort) {
     // This is an early exit case because we don't care that that range