Method undo

ij/src/main/java/ij/plugin/frame/Editor.java:812–828

()

	}	   

	void undo() {
		if (IJ.isWindows()) {
			IJ.showMessage("Editor", "Press Ctrl-Z to undo");
			return;
		}
		if (IJ.debugMode) IJ.log("Undo1: "+undoBuffer.size());
		int position = ta.getCaretPosition();
		if (undoBuffer.size()>1) {
			undoBuffer.remove(undoBuffer.size()-1);
			String text = (String)undoBuffer.get(undoBuffer.size()-1);
			performingUndo = true;
			ta.setText(text);
			if (position<=text.length())
				ta.setCaretPosition(position-offset(position));
			if (IJ.debugMode) IJ.log("Undo2: "+undoBuffer.size()+" "+text);
		}
	}
	
	boolean copy() { 
		String s;