private fun showLoginScreen(message: String, shake: Boolean = false) {
        if (FX.primaryStage.scene.root != loginScreen.root) {
            FX.primaryStage.scene.root = loginScreen.root
            FX.primaryStage.sizeToScene()
            FX.primaryStage.centerOnScreen()
        }

        loginScreen.title = message

        Platform.runLater {
            loginScreen.username.requestFocus()
            if (shake) loginScreen.shakeStage()
        }
    }

    private fun showWorkbench() {
        if (FX.primaryStage.scene.root != workbench.root) {
            FX.primaryStage.scene.root = workbench.root
            FX.primaryStage.sizeToScene()
            FX.primaryStage.centerOnScreen()
        }
    }