UnsupportedOperationException clicking a source model function category in Function Builder

!ENTRY org.eclipse.ui 4 0 2017-03-07 13:27:01.647
!MESSAGE Unhandled event loop exception
!STACK 0
java.lang.UnsupportedOperationException
	at java.util.AbstractCollection.add(AbstractCollection.java:262)
	at java.util.AbstractCollection.addAll(AbstractCollection.java:344)
	at org.teiid.query.function.FunctionLibrary.getFunctionForms(FunctionLibrary.java:150)
	at org.teiid.query.ui.builder.model.FunctionEditorModel.setCategory(FunctionEditorModel.java:267)
	at org.teiid.designer.transformation.ui.builder.expression.FunctionEditor.handleCategorySelected(FunctionEditor.java:261)
	at org.teiid.designer.transformation.ui.builder.expression.FunctionEditor$1.widgetSelected(FunctionEditor.java:130)
	at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:249)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5219)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1340)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4553)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:4143)
	at org.eclipse.jface.window.Window.runEventLoop(Window.java:818)
	at org.eclipse.jface.window.Window.open(Window.java:794)
	at org.teiid.designer.transformation.ui.editors.sqleditor.SqlEditorPanel.showExpressionBuilder(SqlEditorPanel.java:1205)
	at org.teiid.designer.transformation.ui.editors.sqleditor.SqlEditorPanelWrapper.showExpressionBuilder(SqlEditorPanelWrapper.java:123)
	at org.teiid.designer.transformation.ui.editors.sqleditor.actions.LaunchExpressionBuilder.doRun(LaunchExpressionBuilder.java:50)