Inconsistency across user accounts

[ALinuxUser]

I installed Plank for one user, and the configuration icon appeared on the bar.

I ran Plank for another user, and the configuration icon was missing from the bar.

(Also, having learned to live without the configuration icon - by learning of the Ctrl-RightClick trick - I wanted to remove the config. icon from the bar on the first user account; yet, I cannot discover how to.)

Plank 0.11.3 (compiled from source). Mint 18.1 Cinnamom x64.

MMMMMMMMMMMMMMMMMMMMMMMMMmds+.
MMm----::-://////////////oymNMd+` ------------------
MMd /++ -sNMd: OS: Linux Mint 18.1 xenial x86_64
MMNso/` dMM `.::-. .-::.` .hMN: Kernel: 4.8.0-39-generic
ddddMMh dMM :hNMNMNhNMNMNh: `NMm Uptime: 5 hours, 18 minutes
    NMm dMM .NMN/-+MMM+-/NMN` dMM Packages: 3454
    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
    NMm dMM` ..` ... ydm. dMM WM: Mutter (Muffin)
    hMM- +MMd/-------...-:sdds dMM WM Theme: Cinnamon (SimpleX-Grayscale_NJ)
    -NMm- :hNMNNNmdddddddddy/` dMM Theme: Mint-Y [GTK2/3]
     -dMNs-``-::::-------.`` dMM Icons: Paper [GTK2/3]
      `/dMNmy+/:-------------:/yMMM Font: Noto Sans UI 11 [GTK2/3]
         ./ydNMMMMMMMMMMMMMMMMMMMMM CPU: Intel 2 Duo T7500 (2) @ 2.2GHz
            .MMMMMMMMMMMMMMMMMMM GPU: Intel Integrated Graphics
                                     Memory: 2377MB / 7973MB