Thanks, that's probably the issue because I have only an integrated GPU in an intel i5 CPU. I have previously used the geometry editor also with an integrated GPU in another intel i5 CPU (some years older machine) but that was running in Windows.

The openGL version seems to be only 3.0 (the chart in the link suggested it should be at least 4.5), but it cannot be updated to a newer version in this RHEL7.