https://bugs.winehq.org/show_bug.cgi?id=42254
--- Comment #7 from winetaste@gmx.net --- Still in Wine 6.1
The same for every version of iTunes up to 12.10.10.2 (last for Win7/8.1). With the newest one (12.11.0.26*) this is fixed/a different bug.
With this version Wine renders the standard decoration for title bar instead of iTunes' custom one. This happens in KDE only when the window is maximized and in Gnome also in normal window mode.
*installed with "Windows 10" setting and "iTunes64Setup.exe DISABLE_OS_VERSION_CHECK=1" (see Bug 50580)