NPE: Cannot invoke "java.awt.Component.repaint()" because "this.repaintComponent" is null at ListingMiddleMouseHighlightProvider.setHighlightString

[bthiae2934]

Describe the bug
An exception throws when clicking a register in Function Graph with setting Cursor Text Highlight's mouse button set to "left".

To Reproduce
Steps to reproduce the behavior:

1. Load anything in CodeBrowser
2. Edit -> Tool Options, Listing Fields -> Cursor Text Highlight, set mouse button to "LEFT".
3. Navigate to any function and click "Display Function Graph" icon on toolbar.
4. Click a register.
5. Following exception threw:

Cannot invoke "java.awt.Component.repaint()" because "this.repaintComponent" is null
java.lang.NullPointerException: Cannot invoke "java.awt.Component.repaint()" because "this.repaintComponent" is null
	at ghidra.app.plugin.core.codebrowser.ListingMiddleMouseHighlightProvider.clearHighlight(ListingMiddleMouseHighlightProvider.java:216)
	at ghidra.app.plugin.core.codebrowser.ListingMiddleMouseHighlightProvider.setHighlightString(ListingMiddleMouseHighlightProvider.java:204)
	at ghidra.app.plugin.core.codebrowser.ListingMiddleMouseHighlightProvider.buttonPressed(ListingMiddleMouseHighlightProvider.java:195)
	at ghidra.app.plugin.core.functiongraph.mvc.FGController$FgHighlightProvider.buttonPressed(FGController.java:1174)
	at ghidra.app.util.viewer.listingpanel.ListingPanel.buttonPressed(ListingPanel.java:833)
	at docking.widgets.fieldpanel.FieldPanel.lambda$notifyFieldMouseListeners$1(FieldPanel.java:1359)
	at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:318)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:773)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:720)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:714)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:400)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87)
	at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
	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)

---------------------------------------------------
Build Date: 2025-Dec-05 1355 EST
Ghidra Version: 12.0
Java Home: C:\Program Files\Java\jdk-21
JVM Version: Oracle Corporation 21.0.9
OS: Windows 11 10.0 amd64
Workstation: DESKTOP-8SAV2DL

Expected behavior
There should be no NPE.

Screenshots
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Attachments
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Environment (please complete the following information):

• OS: Windows 11
• Java Version: 21.0.9
• Ghidra Version: 12.0
• Ghidra Origin: official GitHub distro

Additional context
Add any other context about the problem here.

[dragonmacher]

I was able to reproduce. Thanks.