Unfortunately we don't have a release date for ExtJS 4.2.3. I checked the file changes for that bug fix, but the 5.0 code is pretty different from both 4.2.2 and 4.2.3. Are you able to test your app against 5.0 to see if the issue is resolved?
Well, I can try to test v5 in a few weeks time. In the meantime, I am using a nightly build (ext-4.2.3-20140616-beta) and it looks like the styles for form elements have changed. I am using Sencha architect, so what I see in the architect is not the same as what is viewed in my browser after saving the project... Is there any way to get Sencha architect to use the nightly build I am using?