Comment 22 for bug 1546328

Actually there are two problems here.

1) The menu

I have taken a look at qjackctl code. It makes some really wrong assumptions about how the system tray icons work. In particular, it doesn't call the tray icon's contextMenu(), but instead intercepts the events and tries to draw a custom menu. This does not work when the system tray is provided by the indicators.

With the latest upstream Git (https://github.com/rncbc/qjackctl/commit/2587df346c8bd259) the situation is a bit better and the menu shows, but it is still a gross hack and this approach is not guaranteed to always work.

2) The icon

Unfortunately indicator-application doesn't fully implement the StatusNotifier specification. In particular, it supports loading icons only from the icon theme, but not the custom icons via IconPixmap. Qt knows about this and adds a workaround for this but only when XDG_CURRENT_DESKTOP=Unity. On Xfce this is not the case, so the workaround is not applied. When appmenu-qt5 is used, it always uses that workaround. I think the best fix for it will be implementing proper support for IconPixmap in indicator-application.