App tray icon didn't show on windows

[cadem]

I attach to app on windows, this app will run with a tray icon. I attached this session successfully, this app window showed. But this app tray icon didn't show on my windows client. The xpra tray icon showed, and I start fcitx with this app, fcitx tray icon showed too. How do I check this problem? I didn't find any error output related to tray in xpra server log.