I just updated my desktop, and everything is fine, except the system tray color changed to an undesirable dark gray color from a light gray background. This did not happen to a second desktop that I just updated though! This makes the pop-up messaging on the system tray difficult to read, because of the dark gray background. I’ve been messing with the Theme, Color, Icons, and so on in the system settings, but I haven’t been able change the system tray color, or change it to what it was before the update. Have anyone else experience this, or know how to fix it?
Developers: How do you reset it back to default color?
Here’s my system info:

System: Host: GAB85M Kernel: 4.13.0-45-generic x86_64 (64 bit gcc: 5.4.0)
Desktop: KDE Plasma 5.13.2 (Qt 5.11.0) Distro: neon 16.04 xenial
Machine: Mobo: Gigabyte model: B85M-DS3H-A v: x.x
Bios: American Megatrends v: F2 date: 08/10/2015

CPU: Quad core Intel Core i7-4790K (-HT-MCP-) cache: 8192 KB
flags: (lm nx sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx) bmips: 31928
clock speeds: max: 4400 MHz 1: 4222 MHz 2: 4280 MHz 3: 4295 MHz 4: 4275 MHz
5: 4288 MHz 6: 4338 MHz 7: 4338 MHz 8: 4236 MHz

Graphics: Card: Intel Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller
bus-ID: 00:02.0
Display Server: X.Org 1.18.4 drivers: (unloaded: fbdev,vesa)
Resolution: 1920x1080@60.00hz, 1920x1080@60.00hz
GLX Renderer: Mesa DRI Intel Haswell Desktop
GLX Version: 3.0 Mesa 18.0.5 Direct Rendering: Yes

Changing system settings kills functionality of System tray 5.13.2.