java.lang.StringIndexOutOfBoundsException: String index out of range: -1
	at java.lang.Throwable.<init>(Throwable.java:74)
	at java.lang.Exception.<init>(Exception.java:38)
	at java.lang.RuntimeException.<init>(RuntimeException.java:43)
	at java.lang.IndexOutOfBoundsException.<init>(IndexOutOfBoundsException.java:40)
	at java.lang.StringIndexOutOfBoundsException.<init>(StringIndexOutOfBoundsException.java:52)
	at java.lang.String.substring(Compiled Code)
	at nLogo.window.cc.TextLine.cursorPos(Compiled Code)
	at nLogo.window.cc.TextLine.showError(TextLine.java:1283)
	at nLogo.window.cc.ExecuteLine.handleCompilerEvent(ExecuteLine.java:377)
	at nLogo.event.CompilerEvent.beHandledBy(CompilerEvent.java:11)
	at nLogo.event.Event.raise(Compiled Code)
	at nLogo.window.CompilerWindow.handleMoreSourceEvent(CompilerWindow.java:307)
	at nLogo.event.MoreSourceEvent.beHandledBy(MoreSourceEvent.java:11)
	at nLogo.event.Event.raise(Compiled Code)
	at nLogo.awt.WidgetPanel.source(WidgetPanel.java:215)
	at nLogo.window.cc.ExecuteLine.executeCurrentBuffer(ExecuteLine.java:185)
	at nLogo.window.cc.ExecuteLine.handleOverflowEvent(ExecuteLine.java:157)
	at nLogo.event.OverflowEvent.beHandledBy(OverflowEvent.java:11)
	at nLogo.event.Event.raise(Compiled Code)
	at nLogo.window.cc.TextLine.handleOverflow(TextLine.java:546)
	at nLogo.window.cc.TextLine.insert(TextLine.java:510)
	at nLogo.window.cc.TextLine.insert(TextLine.java:155)
	at nLogo.window.cc.TextLine.insert(TextLine.java:1184)
	at nLogo.window.cc.TextLine.doInsertKey(TextLine.java:983)
	at nLogo.window.cc.TextLine.keyTyped(TextLine.java:937)
	at java.awt.Component.processKeyEvent(Compiled Code)
	at java.awt.Component.processEvent(Compiled Code)
	at java.awt.Component.dispatchEventImpl(Compiled Code)
	at java.awt.Component.dispatchEvent(Compiled Code)
	at java.awt.EventDispatchThread.run(Compiled Code)