Bug#1115886: kile: The inverse search with external browser "okular" only works if the editor in "okular" is configured as "custom editor" with the command line "kile --new --line %l %f". Without the "--new" option, nothing happens.

[Markus B. Fröb]

This is a bug in Kile, see https://bugs.kde.org/show_bug.cgi?id=491899  
for a description and a workaround.