An issue about the blinking text editor


Hi!
There seems to be something wrong with m newly installed SMT32CubeIDE. When my mouse cursor moves in the text editor area, it will "blink": Its content disappears for a while and then recover. In the attached two screen snapshots of STM32CubeIDE, the text editor is empty in one of them and normal in the other.
My STM32CubeIDE is version 1.10.1 under Ubuntu 20.04.2 LTS.
Could someone advice how to solve this issue?
Regards,
Oliver