I have been an avid user of RSSOwl & now have ported mine OS to Fedora 18. Everything works fine including the transfer of .rssowl2 (backup folder) to new Fedora. However when minimised or exited to tray tray icon is missing...notifications are OK I  too can right-click tray icon.../* Details Added */RssOwl can be downloaded as a zip file. it has a got a binary & an xpm file...You just execute binary (I symlinked it to /bin) & app starts so I manually created .desktop file:[Desktop Entry]Categories=Network;Exec=rssowlIcon=/home/usama/Programs/rssowl/RSSOwl.pngName=RSSOwlTerminal=falseType=ApplicationI converted that .xpm file to .png to be used as desktop icon. Now I copied RSSOwl.png to /usr/share/pixmaps with no success & when copied RSSOwl.png to /usr/share/icons/gnome/24x24/apps well success happened but very tiny icon :(
Tray Icon Missing Rssowl Fedora 18
gnome3;gnome shell
I'm not familiar with that app, but I know that means your icon theme doesn't have the required icon, i.e apps/24/XX.png, A stupid solution is copy it from somewhere, i.e check the Icon= line in /usr/share/applications/XX.desktop, and copy it to your theme dir.P.S does the app icon show correctly when you search for the app?