if (last_selected == f) last_selected = null;
	public void JSLFrameClosed(JSLFrameEvent e) {	    JSLFrame f = e.getJSLFrame();	    windows.remove(f);	    if (windows.size() < 2) {		// toolbar should never be closed, only hidden		if (toolbar.isVisible()) {		    selected = toolbar.getJFrame();		    showState(toolbar, "selected");		} else if (invisible == null) { // !MacUtils.isMac()		    exitAction.actionPerformed(null);		} else {		    ErrorMsg.reportStatus(ErrorMsg.FRAME,		            "All windows closed, but invisible "		            + "frame exists. Not exiting.");		}	    } else {	        showState(f, "closed. " + (windows.size() - 1)                        + " windows still open.");	    }	}