**Issue :** https://bugs.openjdk.java.net/browse/JDK-8193445
**Background :** The CSS performance improvement done in [JDK-8151756](https://bugs.openjdk.java.net/browse/JDK-8151756) had to be backed out due to functional regressions reported in [JDK-8185709](https://bugs.openjdk.java.net/browse/JDK-8185709), [JDK-8183100](https://bugs.openjdk.java.net/browse/JDK-8183100) and [JDK-8168951](https://bugs.openjdk.java.net/browse/JDK-8168951). Refer to [JDK-8183100](https://bugs.openjdk.java.net/browse/JDK-8183100) for more details on this backout. **Description :** This PR reintroduces the CSS performance improvement fix done in [JDK-8151756](https://bugs.openjdk.java.net/browse/JDK-8151756) while addressing the functional regressions that were reported in [JDK-8185709](https://bugs.openjdk.java.net/browse/JDK-8185709), [JDK-8183100](https://bugs.openjdk.java.net/browse/JDK-8183100) and [JDK-8168951](https://bugs.openjdk.java.net/browse/JDK-8168951). For ease of review, I have made two separate commits - 1) [Commit 1](https://github.com/openjdk/jfx/pull/34/commits/d964675ebc2a42f2fd6928b773819502683f2334) - Reintroduces the CSS performance improvement fix done in [JDK-8151756](https://bugs.openjdk.java.net/browse/JDK-8151756) - most of the patch applied cleanly. 2) [Commit 2 ](https://github.com/openjdk/jfx/pull/34/commits/12ea8220a730ff8d98d520ce870691d54f0de00f)- fixes the functional regressions keeping performance improvement intact + adds a system test **Root Cause :** CSS performance improvement fix proposed in [JDK-8151756 ](https://bugs.openjdk.java.net/browse/JDK-8151756)correctly avoids the redundant CSS reapplication to children of a Parent. What was missed earlier in [JDK-8151756 ](https://bugs.openjdk.java.net/browse/JDK-8151756) fix : "CSS reapplication to the Parent itself”. This missing piece was the root cause of all functional regressions reported against [JDK-8151756](https://bugs.openjdk.java.net/browse/JDK-8151756) **Fix :** Fixed the identified root cause. See commit 2. **Testing :** 1. All passing unit tests continue to pass 2. New system test (based on [JDK-8209830](https://bugs.openjdk.java.net/browse/JDK-8209830)) added in this PR - fails before this fix and passes after the fix 3. System test JDK8183100Test continues to pass 4. All test cases attached to regressions [JDK-8185709](https://bugs.openjdk.java.net/browse/JDK-8185709), [JDK-8183100](https://bugs.openjdk.java.net/browse/JDK-8183100) and [JDK-8168951](https://bugs.openjdk.java.net/browse/JDK-8168951) pass with this fix In addition, testing by community with specific CSS performance / functionality will be helpful. ---------------- Commits: - 12ea8220: Fix for functional regressions of JDK-8151756 + add a sytem test - d964675e: Reintroduce JDK-8151756 CSS performance fix Changes: https://git.openjdk.java.net/jfx/pull/34/files Webrev: https://webrevs.openjdk.java.net/jfx/34/webrev.00 Issue: https://bugs.openjdk.java.net/browse/JDK-8193445 Stats: 121 lines in 5 files changed: 104 ins; 0 del; 17 mod Patch: https://git.openjdk.java.net/jfx/pull/34.diff Fetch: git fetch https://git.openjdk.java.net/jfx pull/34/head:pull/34 PR: https://git.openjdk.java.net/jfx/pull/34
