nsHTMLTextAreaElement::OnValueChanged sends ContentStatesChanged whenever it is called. Because textareas usually have a native appearance set this causes nsCSSFrameConstructor::DoContentStateChanged to add the repaint frame hint. We should be smarter and only send this notifications when we need to.

Comment on attachment 484632 [details] [diff] [review] patch >diff --git a/content/html/content/src/nsHTMLInputElement.cpp b/content/html/content/src/nsHTMLInputElement.cpp >--- a/content/html/content/src/nsHTMLInputElement.cpp >+++ b/content/html/content/src/nsHTMLInputElement.cpp >@@ -3850,22 +3850,24 @@ void > void > nsHTMLInputElement::UpdateAllValidityStates(PRBool aNotify) > { >+ PRBool validBefore = IsValid(); > UpdateTooLongValidityState(); > UpdateValueMissingValidityState(); > UpdateTypeMismatchValidityState(); > UpdatePatternMismatchValidityState(); >- >- if (aNotify) { >+ PRBool validAfter = IsValid(); >+ >+ if (aNotify && validBefore != validAfter) { I think |if (validBefore != IsValid() && aNotify)| might be better. No need to save the return value of IsValid() in validAfter and aNotify might be true very often (false mostly while parsing). >diff --git a/content/html/content/src/nsHTMLTextAreaElement.cpp b/content/html/content/src/nsHTMLTextAreaElement.cpp >--- a/content/html/content/src/nsHTMLTextAreaElement.cpp >+++ b/content/html/content/src/nsHTMLTextAreaElement.cpp > NS_IMETHODIMP_(void) > nsHTMLTextAreaElement::OnValueChanged(PRBool aNotify) > { > // Update the validity state >+ PRBool validBefore = IsValid(); > UpdateTooLongValidityState(); > UpdateValueMissingValidityState(); >+ PRBool validAfter = IsValid(); > [...] >+ PRInt32 stateMask = 0; >+ if (validBefore != validAfter) { validBefore != IsValid() ?

Thanks for the comments. I made those changes in my queue.

Mounir, are there other cases where we send ContentStatesChanged notifications when we don't need to? In addition to skipping a lot of unneeded painting fixing this bug also sped up bug 473178, so there might be some good wins to be had.