8252236: TabPane: must keep header of selected tab visible

[kleopatra]

the issue is that the header of the selected tab is not always visible (or kept visible, see report for details)

• initially
• after changing side
• after resizing stage/tabPane
• after modifying the list of tabs

Fixed in TabPaneSkin to notify its TabHeaderArea (== collaborator that is responsible for layout the tabs) whenever its scroll might need an update.

Added tests that fail before and pass after the fix.

Note that there still are issues while/after dragging, which are separated into JDK-8253352

---

Progress

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Issue

• JDK-8252236: TabPane: must keep header of selected tab visible

Reviewers

• Ambarish Rapte (@arapte - Reviewer)
• Kevin Rushforth (@kevinrushforth - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jfx pull/300/head:pull/300
$ git checkout pull/300

[bridgekeeper]

👋 Welcome back fastegal! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[mlbridge]

Webrevs

• 02: Full - Incremental (9b95e0f)
• 01: Full - Incremental (c358382)
• 00: Full (d4c3371)

[kevinrushforth]

/reviewers 2

[openjdk]

@kevinrushforth
The number of required reviews for this PR is now set to 2 (with at least 1 of role reviewers).

[arapte]

In a bid to find more scenarios like you did mention description, I observed two more scenarios when selected tab does not stay in view.

1. Inserting tabs before or removing tabs after selected tab or moving the selected tab, causes the selected tab to go out of view.
2. Rotating TabPane can also take the selected tab out of view. I am little doubtful if it a legitimate issue. The rotations I tried clipped TabPane and TabPane header.
   I think rotation issue can be kept out of scope of this issue, can be filed as a follow on. I leave to it to you to take a call.

About 1, I did quickly verify that it gets fixed by adding invalidateScrollOffset(); call in TabHeaderArea.removeTab(), TabHeaderArea.addTab() and TabHeaderArea.moveTab().
Also If we fix it here, then bug summary might need a change. It currently reflects only initial tab.

[kleopatra]

good catch and many thanks for the evaluation - now all I'll have to do is to write tests to catch them :) Will also update the bug summary as you suggest.

Agree, that the second can be regarded as off scope, as it seems to effect both header and content - will not do anything in this fix.

[kleopatra]

Widened scope of the issue to include problems after modifying the list of tabs: added fix and tests.

Separated dragging issues into a new bug (there's an unrelated isssue when dragging over the leading edge, fixing that might have effects on the trailing edge, so didn't do much to fix the issue/s on the latter except ensuring the visibility after drop).

[arapte]

Looks good to me, left a minor comment.

[arapte]

Looks good to me.

[kevinrushforth]

The fix looks good. Thanks for the additional, well-documented tests!

[openjdk]

@kleopatra This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for more details.

After integration, the commit message for the final commit will be:

8252236: TabPane: must keep header of selected tab visible

Reviewed-by: arapte, kcr

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 8 new commits pushed to the master branch:

• 77a183e: 8209788: Left/Right/Ctrl+A keys not working in editor of ComboBox if popup showing
• d10f948: 8252811: The list of cells in a VirtualFlow is cleared every time the number of items changes
• 47e67b4: 8253123: Switch FX build to use JDK 15 as boot JDK
• 13ab2cb: 8252446: Screen.getScreens() is empty sometimes
• b2e2000: 8252546: Move ObservableValue's equality check and lazy evaluation descriptions to @implSpec
• 976a763: 8240499: Enforce whitespace checking for additional source files
• d6dee34: 8252547: Correct transformations docs in Node
• 0514116: 8246745: ListCell/Skin: misbehavior on switching skin

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[kleopatra]

/integrate

[openjdk]

@kleopatra Since your change was applied there have been 8 commits pushed to the master branch:

• 77a183e: 8209788: Left/Right/Ctrl+A keys not working in editor of ComboBox if popup showing
• d10f948: 8252811: The list of cells in a VirtualFlow is cleared every time the number of items changes
• 47e67b4: 8253123: Switch FX build to use JDK 15 as boot JDK
• 13ab2cb: 8252446: Screen.getScreens() is empty sometimes
• b2e2000: 8252546: Move ObservableValue's equality check and lazy evaluation descriptions to @implSpec
• 976a763: 8240499: Enforce whitespace checking for additional source files
• d6dee34: 8252547: Correct transformations docs in Node
• 0514116: 8246745: ListCell/Skin: misbehavior on switching skin

Your commit was automatically rebased without conflicts.

Pushed as commit 5b42b64.

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