select element hover style inconsistent while native popup is open

#40774159 Filed 2021-06-22 P4 / S5 Blink>Forms>Select

On Windows, a select:hover style is lost while the dropdown is open and never restored when the mouse re-enters the popup.

Repro (Windows)

  1. Open the repro page and hover the select: it turns blue.
  2. Open the dropdown and hover option "Two": stays blue.
  3. Move the mouse to the right, out of the open select: turns white.
  4. Move back left over option "Two": stays white (bug). Expected: blue.
▶ Open repro page

Actual vs expected

Actual (unpatched) Unpatched: select lost :hover while its popup is open
Expected (patched) Patched: select keeps :hover while its popup is open
Step 1 - hovered Select hovered before opening
Step 2 - popup open Popup open, select still hovered

Links

Issue 40774159