Recently I've started coming back to find my CentOS 7 (running GNOME) laptop's screen fully lit and unlocked, even though I haven't done anything on it for [many many] hours (previously it would lock after <some reasonable time>). There's a little alert dialog in in the upper right corner that says "an application has prevented the <something or other about screen saver/lock happening>" without any detail as to what application is responsible.
How can I determine which application is preventing screen locking?
Potentially relevant portion of
xset q output:
Screen Saver: prefer blanking: yes allow exposures: yes timeout: 0 cycle: 0 Colors: default colormap: 0x5a BlackPixel: 0x0 WhitePixel: 0xffffff Font Path: catalogue:/etc/X11/fontpath.d,built-ins DPMS (Energy Star): Standby: 0 Suspend: 0 Off: 0 DPMS is Enabled Monitor is On