If i want to open the properties dialog for other plugins on the panel i can right click the icon and select properties. Same if i want to move or delete. But for the notification area this seems to be rather hard if you dont know exactly where to click. It seems i have the choice of clicking at the border around the icons and between the icons (1 pixel area). That might not be hard if you just have to move the cursor to the very edge of the screen. But maybe something better/logical could be made. I can right click the panel or any other plugin and select panel>panel preferences... select items tab and double click notification area in the list but that is not so quick/smart and not logical that i should click plugin A to make changes to plugin B. Now if i hide some known programs in the list in properties dialog i see an arrow to the right which gives a nice area to right click on and show the menu. So perhaps the solution can be to show the area with the arrow always or something like that. Maybe someone have a good idea.
On Windows Buttons there is similar issue, but there "Ctrl - click" or "Ctrl - right click" brings the context menu for Windows buttons. Maybe Notification Area could be modified to behave accordingly? And of course these would have to be documented well, preferably even in the UI, to make it easy for beginners to configure the great Xfce panel.
Windows Buttons also have an optional handle, that is placed left/top, and you can get the context menu by right-clicking there. Yet again something that could be implemented on Notification area as well, I suppose, and made default.
The notification area is special because it embeds complete GtkWindows, so we can't properly catch those click events afaict. So yes, this is not convenient, but luckily not a showstopper. Please use the panel preferences dialog to edit the preferences if you don't manage to "ctrl + right-click" the border/margin of the "notification area" (aka systray) plugin.
*** Bug 15847 has been marked as a duplicate of this bug. ***