I've been having some weird troubles with indicator icons. I'm using 12.10, but this has been happening since 11.04 came out.
Two applications, Skype and JungleDisk, have little icons that sit in the system tray in the top right corner of the screen. I have added them to the system-tray whitelist in dconf-editor, so they do show up, at least initially.
The problem is that both icons disappear sometimes. This happens even when the applications are open with a visible window - the icon just disappears from the tray. The apps still work, they send notifications, etc, but the icons are gone. It's especially annoying with JungleDisk, because once the icon disappears, the only way to interact with the program is to kill it manually, then relaunch, and open the window before the icon disappears.
Here's the strange thing: if I open the Dash, or hit Super-S to expose all of the workspaces, you can see the icons again. Screenshot with Super-S:

and screenshot while Dash is open:

While the dash is open, the icons in question seem to be sort of hidden by the panel.
Anybody run into this before, or have any thoughts on how to fix?