Icons sometimes disappear from the Panel notification area when Ubuntu 14.04 starts up. Not the same icon disappears every time, and only one icon disappears at a time. This happens infrequently, and I have also seen it happen on older versions of Ubuntu. The next time I start up Ubuntu, all of the Panel icons are back in the notification area of the Panel where they should be.
Here are some examples of icons that have disappeared from the Panel notification area at startup.
- battery indicator
- network indicator
- Thunderbird Mail
- gear icon for accessing functions such as Lock/Log Out/Suspend/Restart/Shut Down, etc. from a dropdown menu
All of these icons have disappeared from the Panel at least once, however the indicator icon for Psensor temperature monitor application which usually takes about one minute after startup to appear on the Panel notification area has never disappeared from the Panel at startup.
How can I make a missing Panel icon reappear without rebooting the operating system? I would prefer a general solution that works for any of the missing icons in the list.