Sensors Widget forgets custom colors when re-opening the Configure Panel window

Description:
    lxqt-panel(taskbar): Sensors Widget forgets custom colors when
    re-opening the Configure Panel window from taskbar
    (booted in livemode).

Expected results:
    Custom colors on the Sensors Widget should stay set until I say so.

Actual results:
    Custom colors on the Sensors Widget are coming and going as
    they please when I re-open the taskbar Configure Panel after
    setting custom colors on the Sensors Widget.

Steps to reproduce:
    0.Boot live cd or usb.

    1.Right-click taskbar, select "Manage Widgets", the Configure Panel
      window will open.

    2.In the Widgets section of the Configure Panel window, click plus
      sign(+) on the right hand side, this will open the Add Plugins
      window.

    3.Scroll down in the Add Plugins window and
      select: "Sensors(sensors)"
              "View readings from hardware sensors.",
      then click Add Widget button, you should see the Sensors widget
      appear on the right hand end of the taskbar, then click Close
      button.

    4.Back in the Configure Panel window, select the Sensors widget you
      just added, then click on the gear icon on the right hand side,
      opening the Sensors Settings window, and select the sensors tab.
      In the column named Color, click a blue (default color) rectangle to
      open the color picker and select a bright color for contrast,
      click OK, you should see the Sensors widget on the taskbar display
      the new color.

    5.OK, here's where it gets good, close all the taskbar config windows
      you have opened, then right-click taskbar, while looking at the
      taskbar Sensors widget, and select Manage Widgets, for me, the
      colors get RESET to default blue. To me, that is a bug.

    6.Now, if you navigate all the way back into the color picker(step 4.)
      and just click OK, with or without selecting a new color, it seems
      to re-parse and reapply the custom color(s)
      (until you right-click taskbar again, and select Manage Widgets)

Tested variations:
    0.What happens when I logout>login?. Picked colors seem to be honored.
    1.What if Sensors Widget can't detect any sensor hardware? Tough beans

Comments:
    I know this is not a particularly egregious bug, but this is my first
    bug report, and I need practice.

    I tend to run Lubuntu in live mode for my daily driver, and for
    testing .iso qa.
    I use the ram/cpu/temp widgets to monitor heavily loaded machines
    compiling, SETI@home, block mining, etc.

Affected versions.
    lubuntu@lubuntu:~$ lsb_release -rd
    Description: Ubuntu Disco Dingo (development branch)
    Release: 19.04
    -------------------------------------------------------
    ProblemType: Bug
    ApportVersion: 2.20.10-0ubuntu18
    Architecture: amd64
    CasperVersion: 1.401
    CurrentDesktop: LXQt
    Date: Mon Jan 21 22:35:05 2019
    DistroRelease: Ubuntu 19.04
    LiveMediaBuild: Lubuntu 19.04 "Disco Dingo" - Alpha amd64 (20190120)
    Package: lxqt-panel 0.13.0-0ubuntu6
    PackageArchitecture: amd64
    ProcVersionSignature: Ubuntu 4.18.0-11.12-generic 4.18.12
    SourcePackage: lxqt-panel
    Tags: disco
    Uname: Linux 4.18.0-11-generic x86_64
    UpgradeStatus: No upgrade log present (probably fresh install)

SHA256SUM:
    fd3fd7743e7e389eda74392e3b276fbaf1e9f904e27321d614ccb3747e72a46f
    *disco-desktop-amd64.iso