Because the DISPLAY is not correctly set in the sandbox.
Created attachment 421137 [details] Patch
Created attachment 421139 [details] Patch
This works for me, thank you very much!
Comment on attachment 421139 [details] Patch Trying cq+ but I suspect this will not work.
Tools/Scripts/svn-apply failed to apply attachment 421139 [details] to trunk. Please resolve the conflicts and upload a new patch.
Committed r273238 (234424@main): <https://commits.webkit.org/234424@main>
<rdar://problem/74591433>