Separate test class added for TreeTableView case. Fix is analogous to JDK-8251480.
------------- Commit messages: - 8285197: TableColumnHeader: calc of cell width must respect row styling (TreeTableView) Changes: https://git.openjdk.java.net/jfx/pull/779/files Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=779&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8285197 Stats: 183 lines in 2 files changed: 179 ins; 1 del; 3 mod Patch: https://git.openjdk.java.net/jfx/pull/779.diff Fetch: git fetch https://git.openjdk.java.net/jfx pull/779/head:pull/779 PR: https://git.openjdk.java.net/jfx/pull/779
