8377727: Ghost caret and focus appear in non‑editable text fields by azuev-java · Pull Request #30758 · openjdk/jdk

azuev-java · 2026-04-15T23:20:00Z

Make caret color closer to the background color so it does appear as disabled caret.

Here is the comparison of default caret and the caret after the fix is applied:
Default white background:
After fix white background:
Default red background:
After fix with red background:

I confirm that I make this contribution in accordance with the OpenJDK Interim AI Policy.

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Change must not contain extraneous whitespace
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Issue

JDK-8377727: Ghost caret and focus appear in non‑editable text fields (Bug - P3)

Reviewers

Phil Race (@prrace - Reviewer)
Dmitry Markov (@dmarkov20 - Reviewer)
Alexey Ivanov (@aivanov-jdk - Reviewer)

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Using Webrev

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…JDK 8u451+ Make caret color closer to the background color so it does appear as disabled caret.

bridgekeeper · 2026-04-15T23:22:02Z

👋 Welcome back kizune! 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.

openjdk · 2026-04-15T23:23:53Z

@azuev-java 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 details.

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

8377727: Ghost caret and focus appear in non‑editable text fields

Reviewed-by: prr, dmarkov, aivanov

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 240 new commits pushed to the master branch:

03996ff: 8382843: Update ProblemList comments for preview features
fc5fabf: 8382634: Remove redundant TLABRefillWasteFraction zero check
135451e: 8381771: Add a check for DNS label not to end with a hyphen
... and 237 more: https://git.openjdk.org/jdk/compare/e79692881fab1d4c986b72a08f73bfc1b19f39b7...master

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openjdk · 2026-04-15T23:24:52Z

@azuev-java The following label will be automatically applied to this pull request:

client

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mlbridge · 2026-04-15T23:28:38Z

Webrevs

01: Full - Incremental (af63b1c8)
00: Full (d68494c8)

openjdk · 2026-04-16T18:53:48Z

The total number of required reviews for this PR has been set to 2 based on the presence of this label: client. This can be overridden with the /reviewers command.

prrace

OK. I'm sure there'll be some opinions about whether it is now too low-contrast, but it does need to be distinguishable from the normal caret, otherwise people may think we didn't change anything.

aivanov-jdk · 2026-04-21T13:00:25Z

+                    int red = (caretColor.getRed() + bg.getRed()) / 2;
+                    int green = (caretColor.getGreen() + bg.getGreen()) / 2;
+                    int blue = (caretColor.getBlue() + bg.getBlue()) / 2;
+                    int alpha = 127;


Would it be enough to change the alpha component of the caret only?

That might be simpler.
It occurred that the code above could cause an IAE since the Color constructor requires values to be in range.
If the caret is white and the bg is say rgb(2, 2,2) then you'll pass 256 and get an exception.
It needs to be clamped.

There are also methods on java.awt.Color
Color.darker()
and
Color.brighter()

which could be used, but you'd first need to examine the caret color and probably the background too, to know which one is appropriate.

ie for a light bg with a dark caret, you'll want to use brighter() to reduce the contrast.
And vice versa.

If the caret is white and the bg is say rgb(2, 2,2) then you'll pass 256

No, i will not. The white is rgb(255, 255, 255) and bg is rgb(2, 2, 2) then i will pass rgb ((2 + 255) / 2, (2 + 255) / 2, (2 + 255) /2) which is rgb(128, 128, 128) which is gray - perfectly fits the purpose of the fix.

Would it be enough to change the alpha component of the caret only?

Not sure it will work good on all color combinations so i did both added alpha value of 50% and brought color half way to the background.

If the caret is white and the bg is say rgb(2, 2,2) then you'll pass 256

No, i will not. The white is rgb(255, 255, 255) and bg is rgb(2, 2, 2) then i will pass rgb ((2 + 255) / 2, (2 + 255) / 2, (2 + 255) /2) which is rgb(128, 128, 128) which is gray - perfectly fits the purpose of the fix.

You're right. I mis-read the parens.

azvegint · 2026-04-21T14:31:02Z

I see an NPE when I focus a disabled text field with the javax.swing.plaf.nimbus.NimbusLookAndFeel LaF enabled.

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException: Cannot invoke "java.awt.Color.getRed()" because "caretColor" is null
        at java.desktop/javax.swing.text.DefaultCaret.paint(DefaultCaret.java:699)
        at java.desktop/javax.swing.plaf.basic.BasicTextUI.paintSafely(BasicTextUI.java:774)
        at java.desktop/javax.swing.plaf.basic.BasicTextUI.paint(BasicTextUI.java:927)
        at java.desktop/javax.swing.plaf.synth.SynthTextFieldUI.paint(SynthTextFieldUI.java:201)
        at java.desktop/javax.swing.plaf.synth.SynthTextFieldUI.update(SynthTextFieldUI.java:185)
        at java.desktop/javax.swing.JComponent.paintComponent(JComponent.java:838)
        at java.desktop/javax.swing.JComponent.paint(JComponent.java:1114)
        at java.desktop/javax.swing.JComponent.paintChildren(JComponent.java:947)
        at java.desktop/javax.swing.JComponent.paint(JComponent.java:1123)
        at java.desktop/javax.swing.JComponent.paintToOffscreen(JComponent.java:5283)
        at java.desktop/javax.swing.BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:255)
        at java.desktop/javax.swing.RepaintManager.paint(RepaintManager.java:1240)
        at java.desktop/javax.swing.JComponent._paintImmediately(JComponent.java:5231)
        at java.desktop/javax.swing.JComponent.paintImmediately(JComponent.java:5041)
        at java.desktop/javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:786)
        at java.desktop/javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:749)
        at java.desktop/javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:699)
        at java.desktop/javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1793)
        at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:323)
        at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:714)
        at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:693)
        at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
        at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
        at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
        at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
        at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
        at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

prrace · 2026-04-21T19:39:46Z

I see an NPE when I focus a disabled text field with the javax.swing.plaf.nimbus.NimbusLookAndFeel LaF enabled.

hmm. That's clearly a problem. And surprising. The existing code doesn't have any obvious protection against null.

prrace · 2026-04-21T19:41:24Z

I see an NPE when I focus a disabled text field with the javax.swing.plaf.nimbus.NimbusLookAndFeel LaF enabled.

hmm. That's clearly a problem. And surprising. The existing code doesn't have any obvious protection against null.
OTOH, it doesn't "use" it - just passes it to setColor() - which just ignores null (!)

I guess this means that the current graphics color is the fall back .. so if there's no caret color you need to use the current graphics color instead.
Then it is for another day as to whether that should really be null.

azuev-java · 2026-04-21T20:07:32Z

I guess this means that the current graphics color is the fall back .. so if there's no caret color you need to use the current graphics color instead. Then it is for another day as to whether that should really be null.

Adding protection from null caret color and null background color (just in case).

prrace

need to avoid the IAE

azuev-java · 2026-04-21T21:17:37Z

need to avoid the IAE

Which happens how?

aivanov-jdk · 2026-04-22T19:14:48Z

+                    if (bg == null) {
+                        g.setColor(caretColor);


Does it make sense to add alpha to the caret if background color is null?

This is a fallback which in theory should never happen because according to documentation it is impossible to set caret color to null, documentation for setCaretColor says:
Setting to null effectively restores the default color.
so i would leave it as is and instead looked at the Nimbus LaF to see why does it return null caret color for the disabled caret. Using the foreground color is a workaround to repeat the current behavior, not a proper solution. It might backfire on custom text component where user paints with some weird color something between text draw and caret painting.

azuev-java · 2026-04-23T06:30:38Z

/integrate

openjdk · 2026-04-23T06:31:57Z

Going to push as commit 635c4b9.
Since your change was applied there have been 247 commits pushed to the master branch:

2fe7ae9: 8381362: C2: assert(_late_inlines.length() == 0 || IncrementalInlineMH || IncrementalInlineVirtual) failed: not empty
6b6f299: 8382316: Unused xtmp in long_to_maskLE8_avx
7e1ed28: 8382606: Enable VectorMinMaxTransforms.java IR tests for RISC-V
... and 244 more: https://git.openjdk.org/jdk/compare/e79692881fab1d4c986b72a08f73bfc1b19f39b7...master

Your commit was automatically rebased without conflicts.

openjdk · 2026-04-23T06:32:09Z

@azuev-java Pushed as commit 635c4b9.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

azuev-java · 2026-04-24T23:35:43Z

/backport jdk26u

openjdk · 2026-04-24T23:37:53Z

@azuev-java the backport was successfully created on the branch backport-azuev-java-635c4b96-master in my personal fork of openjdk/jdk26u. To create a pull request with this backport targeting openjdk/jdk26u:master, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit 635c4b96 from the openjdk/jdk repository.

The commit being backported was authored by Alexander Zuev on 23 Apr 2026 and was reviewed by Phil Race, Dmitry Markov and Alexey Ivanov.

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$ git checkout backport-azuev-java-635c4b96-master
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk26u.git backport-azuev-java-635c4b96-master

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8377727: Ghost caret and focus appear in non‑editable text fields on …

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…JDK 8u451+ Make caret color closer to the background color so it does appear as disabled caret.

openjdk Bot added the client client-libs-dev@openjdk.org label Apr 15, 2026

openjdk Bot added the rfr Pull request is ready for review label Apr 15, 2026

azuev-java changed the title ~~8377727: Ghost caret and focus appear in non‑editable text fields on JDK 8u451+~~ 8377727: Ghost caret and focus appear in non‑editable text fields Apr 15, 2026

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Add null check for caret and background color reported by the component.

af63b1c

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azuev-java requested review from aivanov-jdk and dmarkov20 April 22, 2026 19:09

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azuev-java deleted the JDK-8377727 branch April 24, 2026 23:35

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