`RenderLock1Test`'s instability comes from Windows focus stealing mechanism getting in the way.
The test displays an alert and relies on whether the alert's Button receives focus while other window is rendering in the background. To successfully receive focus on the test Button the application itself must be granted focus first, which [in some cases can be rejected by the OS](https://bugs.openjdk.org/browse/JDK-8351357). On macOS I noticed no issues - the test ran 100 times in a loop and succeeded every time, no matter if Gradle ran with or without daemon. Similarly I ran the test on our CI systems on repeat 100 times and it also succeeded there. On Linux the test does not work because when the alert-displaying Stage is closed the "lost focus" event does not fire. This is a Linux specific issue and it [already is documented in-code with an assumption](https://github.com/openjdk/jfx/blob/master/tests/system/src/test/java/test/renderlock/RenderLockCommon.java#L111). On Windows the focus problems come from aforementioned focus stealing prevention. The solution to this is similar to other tests that showed this problem, which is to run tests using `--no-daemon` flag in Gradle. I similarily tested this by running the test using `--no-daemon` flag on repeat 100 times and the test always passed. I think we can mark this test as stable and include it into the testing pool. --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - Remove unstable flag from RenderLock1Test Changes: https://git.openjdk.org/jfx/pull/2151/files Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=2151&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8237018 Stats: 3 lines in 1 file changed: 0 ins; 2 del; 1 mod Patch: https://git.openjdk.org/jfx/pull/2151.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/2151/head:pull/2151 PR: https://git.openjdk.org/jfx/pull/2151
