GdkDisplayManager issue in Konqueror and Rekonq

I have suddenly started getting crashes with Konqueror and Rekonq which the KDE Bug analyser cannot understand. Immediately after the crash openjdk version “1.8.0_121” is run and the following warning appears

GLib-GObject-WARNING **: cannot register existing type 'GdkDisplayManager'

followed by lots more …

Any suggestions?