on Ubuntu 18 does not work

[Egor]

after upgrade from Ubuntu 16 there is two vertical lines on the transparent background.
If I move mouse over indicator, then two graphs appears and do not changes.
If I click on the indicator then menu appears and show actual values.
Bot there is no graph.

[George (3grciii)]

I have a similar issue: I can confirm that the output generated alternates between the two images attached at the system monitor update interval.

[Siegfried Fuchs (fusi1939)]

It's a common issue with RAM and swap. There are not enough memory. With Ubuntu 18.04 both memories should be greater than 1 GB . The load is often more than 90 % respectively.
With a bit of luck you can check it with
 System Load Indicator
(First I have removed Firefox in the graphical surface and then
 sudo apt install firefox in the Terminal)

[George (3grciii)]

@fusi1939 in my case the problem was resolved by installing Unity desktop.