Codex Desktop on Windows burns particular CPU core while idle if the window is visible.

What version of the Codex App are you using (From “About Codex” dialog)?

26.616.10790.0

What subscription do you have?

plus, previously pro

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

Total CPU percentage may look modest at first glance because the machine has 22 logical processors.
However, the main Codex.exe process continuously consumes a large fraction of one CPU core while the window is visible and idle.
In the captured log, visible idle usage averaged ~3.06% total CPU, which is about 67% of one logical core on this machine.
p95 was ~4.83% total CPU, about 106% of one logical core, with peaks around ~6.53% total CPU, about 144% of one logical core.

codex-cpu.csv

What steps can reproduce the bug?

This is sustained, not just a short spike. The laptop fans spin up loudly while the Codex window is visible, even when I am only reading existing text and not running any agent/tool work. After minimizing the Codex window, CPU usage drops close to zero and the fans calm down.
The load appears to come from the main Codex.exe process, not from codex app-server, node_repl, renderer, or GPU process.

What is the expected behavior?

_No response_

Additional information

_No response_