[bug] sp-picker not selectable on secondary monitor (repro code is included!)

Minimal reproduction:

• on a secondary display, an sp-picker's menu never appears and cannot be used.
• the sp-picker itself takes focus and shows its focus outline, but the menu is never painted.

The panel instruments the DOM at the moment the menu should be visible. Every property we can read is identical on the working and failing displays: the menu is in the document, computed-visible, and correctly sized. Only the painting differs.

Observed in:

• Photoshop 27.9.1
• UXP manifest v5
• Windows 11

Full bug report here:

https://forums.creativeclouddeveloper.com/t/bug-sp-picker-not-selectable-on-secondary-monitor-includes-repro-code/12096/3

• full video
• example plugin code & `.ccx` plugin file
• more-detailed debug notes