About the Power button or the like of icon

good afternoon.
The Zorin OS 10 use as a virtual machine and then install it on Oracle VM VirtualBox.
When you start the virtual machine, an icon of the power button, and the like at the bottom right of the desktop screen may not be displayed. Although it is not always have such a phenomenon occurs.
About the causes and workarounds, if you have person there you know, thank you for your professor.
Thank you.

Never run Zorin as a VM only full install - right-click the panel at bottom of screen and select 'Preferences'. On window that opens, click on 'applets' tab. You should see 'dummy' replica of panel at the very bottom - there should be an 'i' in a blue circle - this is the 'indicator3-applet' - remove and then add back again - this is what works for me on Zorin DE install - please note you could try to install Cairo Dock DE or Cinammon DE as an alternative!

good afternoon.
I received your reply, thank you.
Today, when we start the virtual machine of Zorin OS 10, icons of power button was displayed.
For a while, and I want to take a look at the situation in this state.
Thank you.