Can't edit sketch file!

Forum,

Total noob here with UNO and Macbook Pro.

I open the BLINK sketch, upload it, led blinks... Life is good.

Now, when I try to edit the file .. Nothing happens on screen.
I can move the cursor around with the mouse and the keyboard but again, I can't make any modifications.

I have done a 'save as..' to my desktop to make sure it's not write protected. No change.
I have done 'verify disk permissions'. No change (but do get some errors on java... hmmmm)
I have created a blank sketch... Same symptoms

Here's something interesting when using 'comment/uncomment'. I get the following java errors:

Exception in thread "AWT-EventQueue-0" java.lang.InternalError: Text component read only
at processing.app.syntax.JEditTextArea.setSelectedText(JEditTextArea.java:1269)
at processing.app.Editor.handleCommentUncomment(Editor.java:1730)
at processing.app.Editor$TextAreaPopup$7.actionPerformed(Editor.java:2629)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2028)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2351)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.AbstractButton.doClick(AbstractButton.java:389)
at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1223)
at com.apple.laf.AquaMenuItemUI.doClick(AquaMenuItemUI.java:137)
at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1264)
at java.awt.Component.processMouseEvent(Component.java:6352)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
at java.awt.Component.processEvent(Component.java:6117)
at java.awt.Container.processEvent(Container.java:2085)
at java.awt.Component.dispatchEventImpl(Component.java:4714)
at java.awt.Container.dispatchEventImpl(Container.java:2143)
at java.awt.Component.dispatchEvent(Component.java:4544)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4621)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4282)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4212)
at java.awt.Container.dispatchEventImpl(Container.java:2129)
at java.awt.Window.dispatchEventImpl(Window.java:2478)
at java.awt.Component.dispatchEvent(Component.java:4544)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:635)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

Might this be the source of the problem?

Suggestions anyone?

Thanks!

Rob

Are you the only user account on that MacBook, or are there other users?

I know it sounds too simple but try closing the arduino software and restarting it.
Sometimes strange bugs occur that can be resolved by restarting the software.
BTW I sent you a personal message.

I'm the only user on the system and have admin rights.

Stopping/starting or... reinstalling for that matter.. does not help either.

:-[