The app-office/libreoffice nsplugin conflicts with webkit browsers going as far as to hanging them (https://bugzilla.gnome.org/show_bug.cgi?id=696871). Currently there is no way of disabling it other then uninstalling libreoffice or remove the plugin by hand. PS. It is related to bug #415259 but I'm not sure if it should be duplicate or not
I am actually more inclined in disabling the feature, it is borked mroe than working and nobody is willing to test it and help me make it work.
Fixed by removing the feature for now, if somebody needs it they can work on it.