Eyedropper next to color properties in Effect Controls panel does not apply the sampled color (26.5, macOS) — regression vs 25.6.6

Eyedropper next to color properties in Effect Controls panel does not
apply the sampled color (26.5, macOS) — regression vs 25.6.6

Environment
- After Effects 26.5.0 (also installed: 25.6.6, Beta 27.0)
- macOS 26.2 (25C56), Apple silicon MacBook Pro
- Two displays (scaled external + built-in); reproduces on both

Steps to reproduce
1. New comp, add a solid with a saturated color.
2. Add an adjustment layer, apply the Tint effect.
3. In Effect Controls, click the eyedropper next to "Map White To" and drag
   onto the colored solid in the Composition panel.

Expected
The swatch takes the sampled color.

Actual
Nothing is applied — the swatch stays unchanged. During the drag, the color
field in the Info panel switches from the correct color to black, while the
numeric RGB readout in the Info panel remains correct.

Scope
- The eyedropper INSIDE the Adobe Color Picker dialog (click the swatch,
  then use the dialog's eyedropper) works perfectly in 26.5.
- The same steps work perfectly in After Effects 25.6.6 on the same machine,
  same project, same effect.
- Only the inline eyedropper in the Effect Controls panel is affected —
  i.e. the panel rebuilt in 26.5 ("Effect Controls panel modernization").

Ruled out
- Screen Recording permission: verified granted for the running 26.5 process
  in the system TCC log (kTCCServiceScreenCapture, authValue=2, authReason=4).
- Screen capture path: full-screen and per-window captures both contain the
  sampled color correctly.
- "Hardware Accelerate Composition, Layer, and Footage Panels": off and on.
- Display scaling and multi-monitor setup: reproduces on both displays.
- Third-party ScriptUI panels: all 40 moved out, AE restarted — no change.
- Third-party window manager / event-tapping utility: quit — no change.

Note: this looks related to the known issue already listed for the new panel
("Checkbox actions: if clicking a checkbox doesn't register correctly, ensure
the effect is selected in Effect Controls Panel first") — click handling in
the modernized panel not registering.