> On macOS when the user swipes on a trackpad or Magic Mouse JavaFX sees this > as a scroll gesture. The scene tries to ensure that all the scroll events > generated by the gesture are fired at the same target to ensure that the > gesture's scroll events don't get split between two ScrollPanes. For example, > while a ScrollPane is being scrolled a child ScrollPane might shift until > it's beneath the mouse pointer. Scroll events should not fire at the child > but remain with the parent. > > During the gesture the scene should target the node that's handling the > scrolling (like a ScrollPane) but there's no good way to determine that. > Instead it targets a descendant node, whatever was under the mouse pointer > when the gesture started. This node is likely to shift during the scroll and > if scrolls out of view it might get disconnected from the scene graph. At > that point events fired at it will go nowhere and the gesture will abruptly > stop. > > This PR detects when the gesture target is removed from the scene graph and > attempts to find a new target. > > This bug does not reproduce on Windows since that platform doesn't generate a > SCROLL_STARTED event so the Scene never selects a gesture target. All scroll > events are delivered to whatever node is under the mouse pointer which will > change as the scroll progresses. > > This PR might fix [JDK-8088460](https://bugs.openjdk.org/browse/JDK-8088460) > which shows up in Ensemble if anyone wants to test that. > > Submitting fix for sanity checking and manual testing. Will investigate > creating an automated test for this. > > --------- > - [x] I confirm that I make this contribution in accordance with the [OpenJDK > Interim AI Policy](https://openjdk.org/legal/ai).
Martin Fox has updated the pull request incrementally with one additional commit since the last revision: Consistent handling of null pick node. ------------- Changes: - all: https://git.openjdk.org/jfx/pull/2171/files - new: https://git.openjdk.org/jfx/pull/2171/files/205de3d2..2e15d433 Webrevs: - full: https://webrevs.openjdk.org/?repo=jfx&pr=2171&range=01 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=2171&range=00-01 Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod Patch: https://git.openjdk.org/jfx/pull/2171.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/2171/head:pull/2171 PR: https://git.openjdk.org/jfx/pull/2171
