mainViewer.addSelectionChangedListener(openBrowserAction);
javaEditorAction = new OpenInJavaEditorAction();
mainViewer.addSelectionChangedListener(javaEditorAction);
breakpointAction = new ToggleBreakPointAction(this);
mainViewer.addSelectionChangedListener(breakpointAction);
linkingAction = new ToggleLinkingAction(this);
orientationActions = new ToggleOrientationAction[] {
new ToggleOrientationAction(this, SWT.HORIZONTAL),
new ToggleOrientationAction(this, SWT.VERTICAL) };
}