Calling `UIManager.getDefaults().keySet().contains(key)` and `UIManager.getDefaults().containsKey(key)` produce different results. This is a regression from [JDK-8146330](https://github.com/openjdk/jdk/commit/1e217e7b8bc9bea5e1214c93e5ccb198418a4aa3), where it fixed keys() vs keySet() size mismatch by overriding only` MultiUIDefaults.keySet()` but MultiUIDefaults combines defaults from several places:
- its own local defaults - defaults supplied by the active Look and Feel After JDK-8146330, `keySet() `was changed to list keys from all those places. So it can see a key such as "TabbedPane.isTabRollover" supplied by the Look and Feel. But `containsKey()` was not changed. It still only looks in the object’s own local defaults, not the Look-and-Feel defaults Adding containsKey() to MultiUIDefaults makes it search the same combined set of defaults as keySet() --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - 8390296: Swing MultiUIDefaults#containsKey inconsistancy Changes: https://git.openjdk.org/jdk/pull/32368/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=32368&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8390296 Stats: 106 lines in 2 files changed: 105 ins; 0 del; 1 mod Patch: https://git.openjdk.org/jdk/pull/32368.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/32368/head:pull/32368 PR: https://git.openjdk.org/jdk/pull/32368
