xsession errors

[ALinuxUser]

Hi there.

I get these errors reported in .xsession-errors. *Possibly* the problem owes to a Plant theme rather than to Plank itself. Functionality seems unaffected, but for all I know the errors could be causing slow-downs or visual glitches.

[WARN 15:52:50.659709] [Environment:161] XDG_SESSION_CLASS not set in this environment!
[WARN 15:52:50.659771] [Environment:192] XDG_SESSION_TYPE not set in this environment!

MY ENVIRONMENT

Linux Mint 18.1 x64.
Plank 0.11.4 installed, initially (an ealier version of Plank) via PPA and then (the 0.11.4) via .deb.

OS: Linux Mint 18.1 Serena x86_64
MMNso/` dMM `.::-. .-::.` .hMN: Kernel: 4.10.0-20-generic
ddddMMh dMM :hNMNMNhNMNMNh: `NMm Uptime: 12 minutes
    NMm dMM .NMN/-+MMM+-/NMN` dMM Packages: 3607
    NMm dMM -MMm `MMM dMM. dMM Shell: /bin/bash
    NMm dMM -MMm `MMM dMM. dMM Resolution: 1280x800
    NMm dMM .mmd `mmm yMM. dMM DE: Cinnamon 3.2.7
    NMm dMM` ..` ... ydm. dMM WM: Mutter (Muffin)
    hMM- +MMd/-------...-:sdds dMM WM Theme: New-Minty (SimpleX-Grayscale_NJ)
    -NMm- :hNMNNNmdddddddddy/` dMM Theme: Mint-Y [GTK2/3]
     -dMNs-``-::::-------.`` dMM Icons: Paper [GTK2/3]