Fix a minor bug in MainDemo.wpf Bug : Clicking the "Copy to clipboard" button in IconPackView will cause an exception to be thrown. Solution is based on StackOverflow answers : https://stackoverflow.com/questions/12769264/openclipboard-failed-when-copy-pasting-data-from-wpf-datagrid
Fix a minor bug in MainDemo.wpf
Bug : Clicking the "Copy to clipboard" button in IconPackView will cause an exception to be thrown.
Solution is based on StackOverflow answers : https://stackoverflow.com/questions/12769264/openclipboard-failed-when-copy-pasting-data-from-wpf-datagrid

DingpingZhang/MaterialDesignInXamlToolkit,ButchersBoy/MaterialDesignInXamlToolkit,ButchersBoy/MaterialDesignInXamlToolkit,ButchersBoy/MaterialDesignInXamlToolkit