remove obsolete property. I'm not gonna go semver on this one, it's been obsolete for a while
remove obsolete property. I'm not gonna go semver on this one, it's been obsolete for a while

DingpingZhang/MaterialDesignInXamlToolkit,tipunch74/MaterialDesignInXamlToolkit,tipunch74/MaterialDesignInXamlToolkit,ButchersBoy/MaterialDesignInXamlToolkit,ButchersBoy/MaterialDesignInXamlToolkit,ButchersBoy/MaterialDesignInXamlToolkit,tipunch74/MaterialDesignInXamlToolkit