To illustrate the difference between the old and new title bar patterns I created an example image.
Code:
https://www.media!fire.com/file/puz3dag4m4wfdm3/Patterns.ilbm.lha
Also uploaded to The Zone. 320×400 1-plane, load into any image viewer (e.g. MultiView SCREEN). If using WinUAE, enable vsync and set interlaced line mode to "Double, fields+".
You should notice that all parts with the "old" pattern flicker significantly more than areas of "new" pattern.