Lot of errors reported in unified diff after click on "hide diff" button

[iloveeclipse]

Using latest nightly with unified diff preference enabled.

1. Double click in the history view on a file changed in some commit, like on team/bundles/org.eclipse.compare/compare/org/eclipse/compare/contentmergeviewer/TextMergeViewer.java from 556f657.
2. Unified diff editor opens
3. Clicking on some new icons like "hide diff" produce errors in the log.
4. Just scrolling in the editor afterwards continuously produces new errors.e

eclipse.buildId=4.41.0.I20260616-0637
java.version=25
java.vendor=Eclipse Adoptium
BootLoader constants: OS=linux, ARCH=x86_64, WS=gtk, NL=en_US
Command-line arguments:  -os linux -ws gtk -arch x86_64 -data /data/4x_platform_workspace

org.eclipse.ui
Error
Tue Jun 16 10:09:59 CEST 2026
Unhandled event loop exception

java.lang.IllegalArgumentException: Argument not valid
	at org.eclipse.swt.SWT.error(SWT.java:4915)e
	at org.eclipse.swt.SWT.error(SWT.java:4849)
	at org.eclipse.swt.SWT.error(SWT.java:4820)
	at org.eclipse.swt.graphics.GC.setFont(GC.java:3216)
	at org.eclipse.compare.unifieddiff.internal.UnifiedDiffCodeMiningProvider$UnifiedDiffLineHeaderCodeMining.draw(UnifiedDiffCodeMiningProvider.java:667)
	at org.eclipse.jface.internal.text.codemining.CodeMiningLineHeaderAnnotation.draw(CodeMiningLineHeaderAnnotation.java:262)
	at org.eclipse.jface.internal.text.codemining.CodeMiningLineHeaderAnnotation.draw(CodeMiningLineHeaderAnnotation.java:216)
	at org.eclipse.jface.text.source.inlined.InlinedAnnotationDrawingStrategy.draw(InlinedAnnotationDrawingStrategy.java:212)
	at org.eclipse.jface.text.source.inlined.InlinedAnnotationDrawingStrategy.draw(InlinedAnnotationDrawingStrategy.java:154)
	at org.eclipse.jface.text.source.inlined.InlinedAnnotationDrawingStrategy.draw(InlinedAnnotationDrawingStrategy.java:101)
	at org.eclipse.jface.text.source.AnnotationPainter.drawDecoration(AnnotationPainter.java:1472)
	at org.eclipse.jface.text.source.AnnotationPainter.handleDrawRequest(AnnotationPainter.java:1433)
	at org.eclipse.jface.text.source.AnnotationPainter.paintControl(AnnotationPainter.java:1378)
	at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:272)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:91)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5888)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1659)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1685)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1668)
	at org.eclipse.swt.widgets.Control.gtk_draw(Control.java:3908)
	at org.eclipse.swt.widgets.Scrollable.gtk_draw(Scrollable.java:394)
	at org.eclipse.swt.widgets.Composite.gtk_draw(Composite.java:512)
	at org.eclipse.swt.widgets.Canvas.gtk_draw(Canvas.java:173)
	at org.eclipse.swt.widgets.Widget.windowProc(Widget.java:2632)
	at org.eclipse.swt.widgets.Control.windowProc(Control.java:6865)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:6200)
	at org.eclipse.swt.internal.gtk3.GTK3.gtk_main_do_event(Native Method)
	at org.eclipse.swt.widgets.Display.eventProc(Display.java:1621)
	at org.eclipse.swt.internal.gtk3.GTK3.gtk_main_iteration_do(Native Method)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:4532)

[tobiasmelcher]

Thanks a lot for reporting the issue. I'll take a look.