Java onShortcut command not working

Can someone help me with onShortcut thing?

I have OnClick function for the below, but onShortcut alt+R not working, any help would be appreciated.

myPanel.timeSavers.MyTools_tab.nullButton.shortcutKey='R';

myPanel.timeSavers.MyTools_tab.nullButton.onShortcutKey=myPanel.timeSavers.MyTools_tab.nul lButton.onClick;

myPanel.timeSavers.MyTools_tab.defaultElement=myPanel.timeSavers.MyTools_tab.nullButton;

Thanks