top and side menues flickering while moving mouse


I am trying LO 7.0.x on Xubuntu 18.04

LO 6.x works fine but 7.x causes a major problem as the top and side menus continuously flicker when I move the mouse.
switching OpenCL on and off does not have an impact on this.

Any ideas what to do?

thanks Robert

can you show us your Help-About dialog?

sorry, I do not know how to answer this question

sorry, I do not know how to answer this question

You don’t know how to move to menu Help -> About LibreOffice and to click the Copy all version information in English-Button right of Version Information ?

image description

OK, now I know, please see here:

Version: / LibreOffice Community
Build ID: dd797d330b34196606d0870aaa694e9504402ca1
CPU threads: 8; OS: Linux 4.15; UI render: default; VCL: gtk3
Locale: en-US (en_US.UTF-8); UI: en-US
Calc: threaded

the program is installed via: sudo snap install libreoffice

just checked: the flickering is not only with mouse movements but also when typing characters and it continuous for some seconds when neither the mouse is moved nor anything is typed

What Linux distro do you use?

Xubuntu - does this answer your question?