This is a request vor enchancement. A new version of Whisker Menu got released which fixes a couple of bugs. If possible please release a rpm package. Request for Fedora 20 package. http://gottcode.org/xfce4-whiskermenu-plugin/
xfce4-whiskermenu-plugin-1.4.2-1.fc20 has been submitted as an update for Fedora 20. https://admin.fedoraproject.org/updates/xfce4-whiskermenu-plugin-1.4.2-1.fc20
Package xfce4-whiskermenu-plugin-1.4.2-1.fc20: * should fix your issue, * was pushed to the Fedora 20 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing xfce4-whiskermenu-plugin-1.4.2-1.fc20' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2014-17718/xfce4-whiskermenu-plugin-1.4.2-1.fc20 then log in and leave karma (feedback).
xfce4-whiskermenu-plugin-1.4.2-1.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.