change: explicitly disable NSG creation on Flatpak

dzgui/strings/wizard.py

@@ -71,6 +71,7 @@ checkbox_steam_shortcut = (
         "This creates a standalone copy of DZGUI and adds it to Steam. "
         "You <b>must restart Steam</b> for the shortcut to appear. This will not replace or update existing shortcuts. "
         "If you update DZGUI when it is launched via Steam, updates will be applied to the Steam version. "
+        "Not available if you selected the Flatpak client as your Steam default."
     ),
 )
 checkbox_start_menu = (

dzgui/views/dialogs/wizard.py

@@ -12,6 +12,7 @@ from dzgui.const.constants import (
     APP_NAME,
     APP_NAME_LOWER,
     HERO_PATH,
+    FLATPAK_STEAM_PATH,
     LEGACY_CONFIG_PATH,
 )
 from dzgui.const.boilerplate import config_boilerplate
@@ -624,6 +625,12 @@ class ShortcutCreationPage(OptionalPageMixin, EnumeratedWizardPage):  # type: ig
         self.add_start(self.checks_area)
         self.show_all()
         self.connect("map", self._on_map)
+        self.connect("map", self._toggle_checkbox)
+
+    def _toggle_checkbox(self, page: "EnumeratedWizardPage") -> None:
+        if FLATPAK_STEAM_PATH in self.steam_path:
+            self.steam_checkbox.set_active(False)
+            self.steam_checkbox.set_sensitive(False)
 
     def _on_start_menu_toggled(self, button: Gtk.CheckButton) -> None:
         state = button.get_active()