RFR: 8353488: Open some JComboBox bugs 3 [v3]

[Alisen Chung]

> Opening some JComboBox bugs

Alisen Chung has updated the pull request incrementally with one additional commit since the last revision:

  add volatile

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/24767/files
  - new: https://git.openjdk.org/jdk/pull/24767/files/68ba2ec0..44b3691d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24767&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24767&range=01-02

  Stats: 4 lines in 2 files changed: 2 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/24767.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24767/head:pull/24767

PR: https://git.openjdk.org/jdk/pull/24767