When using Ubuntu focal it is difficult to work with the IDE. If you need more performance and a working copy and paste change to xubuntu-Desktop what is working much better with Xojo. You can install xubuntu-Desktop with
sudo apt-get install xubuntu-desktop
After you will see that when using xubuntu the IDE becomes much faster and copy and paste is working more reliable and also faster. Makes it a bit more nice to work under linux.
Please do not forget: because of the deprecated libwebkit-3 there is a problem with the help files and with installing xojo as normal. You would have to use the tar-gz archive for installing it because it is not possible to install without the dependencie and will refuse or will make it needed to apt --fix-broken install the package manager before using another deb on the system what will erase xojo.