[DiffPanel] new content not saved if the original file has been modified

[stefanofornari]

Step to reproduce:

1. Open and change a file
2. Open an interactive chat session
3. Ask the agent to modify the file above with some content -> DiffPanel to review the change
4. accept the changes

Expected

• the changes are applied to the file and saved

Actual

• the file is not changed, silently hiding the exception below

org.openide.filesystems.FileAlreadyLockedException: /home/ste/Projects/jeddict-ai/src/test/java/io/github/jeddict/ai/lang/JeddictJsonCodecFactoryTest.java
	at org.netbeans.modules.masterfs.filebasedfs.fileobjects.LockForFile.registerLock(LockForFile.java:86)
	at org.netbeans.modules.masterfs.filebasedfs.fileobjects.LockForFile.tryLock(LockForFile.java:75)
	at org.netbeans.modules.masterfs.filebasedfs.fileobjects.FileObj.lock(FileObj.java:391)
	at org.openide.filesystems.FileObject.getOutputStreamImpl(FileObject.java:801)
	at org.openide.filesystems.FileObject.getOutputStream(FileObject.java:797)
[catch] at io.github.jeddict.ai.components.diff.DiffPaneController.save(DiffPaneController.java:130)
	at io.github.jeddict.ai.components.diff.DiffPane.lambda$new$1(DiffPane.java:118)
	at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1972)
	at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2314)
	at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:407)
	at java.desktop/javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)
	at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279)
	at java.desktop/java.awt.Component.processMouseEvent(Component.java:6621)
	at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3398)
	at java.desktop/java.awt.Component.processEvent(Component.java:6386)
	at java.desktop/java.awt.Container.processEvent(Container.java:2266)
	at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:4996)
	at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2324)
	at java.desktop/java.awt.Component.dispatchEvent(Component.java:4828)
	at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4948)
	at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4575)
	at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4516)
	at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2310)
	at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2780)
	at java.desktop/java.awt.Component.dispatchEvent(Component.java:4828)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:775)
	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.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:98)
	at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:747)
	at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:400)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87)
	at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:744)
	at org.exbin.utils.guipopup.NetBeansPopupMenu$PopupEventQueue.dispatchEvent(NetBeansPopupMenu.java:158)
	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)

Workaround
Make sure to save the original file before accepting the changes