This fixes the issue adressed here https://bugs.openjdk.org/browse/JDK-8222454
The added TreeTableViewTests were failing without the main code changes. I added the other tests to ensure the consistent functionality of related cell based components. The method getItemCount() needed to be moved to CellBehaviorBase to do the necessary index check in doSelect() below. All subclasses now implement this method based on the cell container. There is still some refactoring potential here, to reduce code duplications and ensure consistent behavior of all cell based components. This could be done in a follow-up PR. ------------- Commit messages: - 8222454: Fix nullpointer in TreeTableRowBehavior Changes: https://git.openjdk.org/jfx/pull/2129/files Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=2129&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8222454 Stats: 178 lines in 11 files changed: 144 ins; 21 del; 13 mod Patch: https://git.openjdk.org/jfx/pull/2129.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/2129/head:pull/2129 PR: https://git.openjdk.org/jfx/pull/2129
