Bug 394950

Every once in a while, the panel stops refreshing for some reason (I still haven't noticed any obvious trigger, but this might just be because I usually don't notice the bug right away). My widgets just stop refreshing (so the clock is stuck on a specific time for instance). Hovering over a tray icon doesn't highlight it like it should, however I still get a tooltip and I can still click it.

Here are my journalctl logs from the time my clock got stuck:

```
Jun 02 12:41:55 NATHAN-PC dbus-daemon[660]: [system] Activating via systemd: service name='org.bluez' unit='dbus-org.bluez.service' requested by ':1.499' (uid=1000 pid=13854 comm="/opt/visual-studio-code/code ")
Jun 02 12:41:55 NATHAN-PC dbus-daemon[660]: [system] Activation via systemd failed for unit 'dbus-org.bluez.service': Unit dbus-org.bluez.service not found.
Jun 02 12:42:46 NATHAN-PC dbus-daemon[660]: [system] Activating via systemd: service name='org.bluez' unit='dbus-org.bluez.service' requested by ':1.531' (uid=1000 pid=14203 comm="/opt/discord/Discord")
Jun 02 12:42:46 NATHAN-PC dbus-daemon[660]: [system] Activation via systemd failed for unit 'dbus-org.bluez.service': Unit dbus-org.bluez.service not found.
Jun 02 12:42:46 NATHAN-PC kernel: NVRM: GPU at PCI:0000:01:00: GPU-6457b8f4-8c89-f125-0406-59101cc9df62
Jun 02 12:42:46 NATHAN-PC kernel: NVRM: Xid (PCI:0000:01:00): 31, Ch 00000028, engmask 00000101, intr 10000000
```

I use the latest NVidia propietary drivers from my package manager (version 396.24) on a GTX 980. Sometimes plasma crashes but immediately recovers, which might be linked (I will update this bug report next time it happens to see if it has anything to do with it).

This problem has been happening for at least a few months now (so it's not specific to one version).