When a subtree is moved in a `TreeTableView` , the visuals don’t update until a resize or expand/collapse. The `TreeTableViewSkin` only rebuilds cells when the expanded row count changes. This PR makes the skin to detect structural changes on `childrenModificationEvent` using new variable `treeStructureDirty`, and in `updateItemCount()` call `requestRebuildCells()` to refresh the visuals.
------------- Commit messages: - Added new treeStructureDirty Changes: https://git.openjdk.org/jfx/pull/1971/files Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1971&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8356770 Stats: 11 lines in 1 file changed: 10 ins; 0 del; 1 mod Patch: https://git.openjdk.org/jfx/pull/1971.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/1971/head:pull/1971 PR: https://git.openjdk.org/jfx/pull/1971
