Add StageBackgroundView and related tests for plain background functionality

- Implemented StageBackgroundView class for managing sky and plain backgrounds in the stage.
- Added functionality to set background type and color, bind camera, and apply themes.
- Created test_phase19_plain_background.gd to validate plain background behavior and migration.
- Developed test_phase19_starter_chooser_layout.gd to ensure proper layout and functionality of the starter chooser.
- Included visual capture tests for UI elements and interactions.

scripts/editors/stage/sandbox_stage.gd

@@ -50,7 +50,7 @@ const STAGE_MODAL_VIEWS_SCRIPT := preload("res://scripts/editors/stage/stage_mod
 const STAGE_THEME_CONTROLLER_SCRIPT := preload("res://scripts/editors/stage/stage_theme_controller.gd")
 const STAGE_TARGET_CAPTURE_SCRIPT := preload("res://scripts/editors/stage/stage_target_capture_session.gd")
 const STAGE_SCENERY_CONTROLLER_SCRIPT := preload("res://scripts/editors/stage/stage_scenery_controller.gd")
-const STAGE_SKY_VIEW_SCRIPT := preload("res://scripts/stage/scenery/stage_sky_view.gd")
+const STAGE_BACKGROUND_VIEW_SCRIPT := preload("res://scripts/stage/scenery/stage_background_view.gd")
 const STAGE_DRAW_ORDER_SCRIPT := preload("res://scripts/stage/stage_draw_order.gd")
 const STAGE_WALL_PANEL_SCRIPT := preload("res://scripts/stage/scenery/stage_wall_panel.gd")
 const STAGE_BACKGROUND_GROUND_SCRIPT := preload("res://scripts/stage/scenery/stage_background_ground.gd")
@@ -258,13 +258,21 @@ var _spawner: StageSpawner
 var _selection: StageSelection
 var _gizmos: StageGizmos
 var _stage_input_ready: bool = false
+var _startup_scene_applied: bool = false
+var _startup_starter_chooser_pending: bool = false
+var _startup_starter_chooser_shown: bool = false
 var _grid: StageGrid
 var _spatial_index: StageSpatialIndex
 var _terrain_painter: StageTerrainPainter
 var _scenery_controller: StageSceneryController
 var _sky_layer: CanvasLayer
 var _sky_view: StageSkyView
+var _background_view: StageBackgroundView
 var _sky_id: StringName = &"sky_neutral"
+var _background_kind: StringName = &"sky"
+var _plain_color: Color = Color("#F5EFE0")
+var _plain_color_draft_active: bool = false
+var _plain_color_draft: Color = Color("#F5EFE0")
 var _new_ground_finish: StringName = &"finish_ground_grass"
 var _hosted_prop_editor: PropEditor
 var _hosted_artwork_path: String = ""
@@ -1850,6 +1858,8 @@ func set_mode(mode: StageMode) -> void:
 		_show_toast("Finish or cancel speech editing first.")
 		_sync_mode_buttons()
 		return
+	if _plain_color_draft_active:
+		_close_selector()
 	_cancel_surface_color_preview()
 	if _scenery_controller != null:
 		if _scenery_controller.is_group_preview_pending():
@@ -2513,6 +2523,74 @@ func _mark_scene_dirty() -> void:
 		_paused_edit_autosave_remaining = 1.0
 
 
+func _refresh_background_view() -> void:
+	if _background_view != null:
+		var displayed_color: Color = _plain_color_draft if _plain_color_draft_active else _plain_color
+		_background_view.set_background(_background_kind, _sky_id, displayed_color)
+		_sky_view = _background_view.get_sky_view()
+	_update_grid_background_style()
+
+
+func _commit_background_kind(kind: StringName, sky_id: StringName = &"") -> void:
+	var next_kind: StringName = &"plain" if kind == &"plain" else &"sky"
+	var next_sky: StringName = sky_id if not sky_id.is_empty() else _sky_id
+	var changed: bool = _background_kind != next_kind or _sky_id != next_sky
+	_background_kind = next_kind
+	_sky_id = next_sky
+	_refresh_background_view()
+	if _asset_browser != null:
+		_asset_browser.set_background_state(_background_kind, _sky_id, _plain_color)
+	if changed:
+		_mark_scene_dirty()
+
+
+func _preview_plain_color(color: Color) -> void:
+	_plain_color_draft = _opaque_stage_color(color)
+	_plain_color_draft_active = true
+	_refresh_background_view()
+
+
+func _cancel_plain_color_preview() -> void:
+	if not _plain_color_draft_active:
+		return
+	_plain_color_draft_active = false
+	_plain_color_draft = _plain_color
+	_refresh_background_view()
+
+
+func _commit_plain_color(color: Color) -> void:
+	var next_color: Color = _opaque_stage_color(color)
+	var changed: bool = _canonical_surface_color(_plain_color) != _canonical_surface_color(next_color)
+	_plain_color = next_color
+	_plain_color_draft = next_color
+	_plain_color_draft_active = false
+	_refresh_background_view()
+	_record_recent_surface_color(next_color)
+	if _asset_browser != null:
+		_asset_browser.set_background_state(_background_kind, _sky_id, _plain_color)
+	if changed:
+		_mark_scene_dirty()
+
+
+func _opaque_stage_color(color: Color) -> Color:
+	return Color(color.r, color.g, color.b, 1.0)
+
+
+func _update_grid_background_style() -> void:
+	if _grid == null:
+		return
+	var displayed_color: Color = _plain_color_draft if _plain_color_draft_active else _plain_color
+	var plain_active: bool = _background_kind == &"plain"
+	_grid.set_background_treatment(
+		plain_active,
+		displayed_color,
+		_sandbox_theme.color("grid.plain_light_minor", Color("#11182120")) if _sandbox_theme != null else Color("#11182120"),
+		_sandbox_theme.color("grid.plain_light_major", Color("#11182148")) if _sandbox_theme != null else Color("#11182148"),
+		_sandbox_theme.color("grid.plain_dark_minor", Color("#FFFFFF25")) if _sandbox_theme != null else Color("#FFFFFF25"),
+		_sandbox_theme.color("grid.plain_dark_major", Color("#FFFFFF58")) if _sandbox_theme != null else Color("#FFFFFF58")
+	)
+
+
 func _set_scene_dirty(value: bool) -> void:
 	if _document != null:
 		_document.set_dirty(value)
@@ -2533,6 +2611,8 @@ func _collect_scene_data(is_autosave: bool = false) -> Dictionary:
 	var document_metadata: Dictionary = {
 		"scene_name": _scene_name,
 		"sky_id": String(_sky_id),
+		"background_kind": String(_background_kind),
+		"plain_color": _canonical_surface_color(_plain_color),
 		"metadata": _document.metadata_for_snapshot(is_autosave),
 	}
 	return _scene_adapter.collect(_world, _authored, _event_rules, camera_state, document_metadata)
@@ -2613,6 +2693,7 @@ func _validate_queues_for_save() -> String:
 
 func _reset_scene_content() -> void:
 	set_mode(StageMode.EDIT)
+	_cancel_plain_color_preview()
 	_cancel_surface_color_preview()
 	if _scenery_erase_piece_dialog != null:
 		_scenery_erase_piece_dialog.hide()
@@ -2622,8 +2703,9 @@ func _reset_scene_content() -> void:
 	_cancel_scenery_repair_preview()
 	_scenery_repair_target = null
 	_sky_id = &"sky_neutral"
-	if _sky_view != null:
-		_sky_view.set_sky(_sky_id)
+	_background_kind = &"sky"
+	_plain_color = Color("#F5EFE0")
+	_refresh_background_view()
 	if _scenery_controller != null:
 		_scenery_controller.exit_tool()
 		_scenery_controller.cancel_group()
@@ -2655,11 +2737,19 @@ func _apply_scene_data(data: Dictionary, source_path: String, is_recovery: bool)
 	source_path = CONTENT_PATHS.canonicalize(source_path)
 	if _scene_adapter == null:
 		return false
+	if _plain_color_draft_active:
+		_close_selector()
+	_cancel_plain_color_preview()
 	var was_suppressed: bool = _suppress_dirty
 	_suppress_dirty = true
 	_reset_scene_content()
 	var adapter_result: Dictionary = _scene_adapter.apply(data, _world, _spawner)
 	_sky_id = StringName(String(adapter_result.get("sky_id", "sky_neutral")))
+	_background_kind = StringName(String(adapter_result.get("background_kind", "sky")))
+	_plain_color = STAGE_SCENE_IO.color_from_data(
+		adapter_result.get("plain_color", STAGE_SCENE_IO.DEFAULT_PLAIN_COLOR),
+		Color("#F5EFE0")
+	)
 	var loaded_nodes: Array[Node2D] = adapter_result.get("loaded_nodes", [])
 	for node: Node2D in loaded_nodes:
 		_finalize_placed_node(node)
@@ -2683,8 +2773,7 @@ func _apply_scene_data(data: Dictionary, source_path: String, is_recovery: bool)
 	var camera_data: Dictionary = raw_camera as Dictionary if raw_camera is Dictionary else {}
 	_camera.global_position = STAGE_SCENE_IO.data_to_vector(camera_data.get("position"), DEFAULT_CAMERA_POSITION)
 	_camera.zoom = Vector2.ONE * clampf(float(camera_data.get("zoom", DEFAULT_CAMERA_ZOOM)), min_zoom, max_zoom)
-	if _sky_view != null:
-		_sky_view.set_sky(_sky_id)
+	_refresh_background_view()
 	var raw_metadata: Variant = data.get("metadata", {})
 	var metadata: Dictionary = raw_metadata as Dictionary if raw_metadata is Dictionary else {}
 	if _document != null:
@@ -2712,6 +2801,7 @@ func _apply_scene_data(data: Dictionary, source_path: String, is_recovery: bool)
 		_add_recent_scene(source_path)
 		if _document != null:
 			_document.remove_autosave()
+	_startup_scene_applied = true
 	return true
 
 func _show_scene_load_warnings(warnings: Array[String]) -> void:
@@ -2782,20 +2872,79 @@ func _update_scene_chrome() -> void:
 	_refresh_status()
 
 
-func _check_autosave_recovery() -> void:
+func _check_autosave_recovery(show_starter_chooser_after_discard: bool = false) -> void:
 	if _document == null:
+		if show_starter_chooser_after_discard:
+			_queue_startup_starter_chooser()
 		return
 	var inspection: Dictionary = _document.inspect_autosave()
 	if not bool(inspection.get("available", false)):
+		if show_starter_chooser_after_discard:
+			_queue_startup_starter_chooser()
 		return
 	var autosave_data: Dictionary = inspection.get("data", {}) as Dictionary
 	var dialog := ConfirmationDialog.new()
 	dialog.name = "AutosaveRecoveryDialog"; dialog.title = "Recover Sandbox Scene?"; dialog.dialog_text = "A previous Play session was not closed cleanly. Recover it?"
 	dialog.confirmed.connect(func() -> void: _apply_scene_data(autosave_data, AUTOSAVE_PATH, true); dialog.queue_free())
-	dialog.canceled.connect(func() -> void: _document.remove_autosave(); dialog.queue_free())
+	dialog.canceled.connect(func() -> void:
+		_document.remove_autosave()
+		dialog.queue_free()
+		if show_starter_chooser_after_discard:
+			_queue_startup_starter_chooser()
+	)
 	get_node(NodePath("UI")).add_child(dialog); _apply_dialog_theme(dialog); dialog.popup_centered()
 
 
+func _queue_startup_starter_chooser() -> void:
+	if _startup_starter_chooser_pending or _startup_starter_chooser_shown:
+		return
+	_startup_starter_chooser_pending = true
+	call_deferred("_present_startup_starter_chooser")
+
+
+func _present_startup_starter_chooser() -> void:
+	while _startup_starter_chooser_pending and is_inside_tree():
+		if not _stage_input_ready or _startup_modal_is_visible():
+			await get_tree().process_frame
+			continue
+		if get_tree().current_scene != self or _startup_scene_applied or current_mode != StageMode.EDIT or not _current_scene_path.is_empty() or _hosted_prop_editor != null:
+			_startup_starter_chooser_pending = false
+			return
+		_startup_starter_chooser_pending = false
+		_startup_starter_chooser_shown = true
+		_open_selector("starters")
+		return
+	_startup_starter_chooser_pending = false
+
+
+func _startup_modal_is_visible() -> bool:
+	if _selector_open or _speech_composer_is_open():
+		return true
+	var ui_layer: CanvasLayer = _chrome.get_canvas_layer() if _chrome != null else null
+	if ui_layer != null:
+		for child: Node in ui_layer.get_children():
+			var window := child as Window
+			if window != null and window.visible:
+				return true
+	for dialog: Window in [
+		_cli_error_dialog,
+		_speech_recovery_dialog,
+		_speech_save_gate_dialog,
+		_scene_open_dialog,
+		_scene_save_dialog,
+		_unsaved_changes_dialog,
+		_rename_scene_dialog,
+		_missing_assets_dialog,
+		_missing_scenery_dialog,
+		_scenery_repair_confirm_dialog,
+		_group_preview_save_dialog,
+		_confirm_dialog,
+	]:
+		if dialog != null and is_instance_valid(dialog) and dialog.visible:
+			return true
+	return false
+
+
 func _handle_cli_startup(args: Array) -> void:
 	if OS.get_environment("STICKMAN_WALK_DEBUG") == "1":
 		print("[WalkDebug] CLI_STARTUP args=%s" % [args])
@@ -2806,7 +2955,7 @@ func _handle_cli_startup(args: Array) -> void:
 		return
 	var scene_path := String(result.get("scene_path", ""))
 	if scene_path.is_empty():
-		_check_autosave_recovery()
+		_check_autosave_recovery(true)
 		return
 	if _document != null and _document.has_autosave():
 		_document.remove_autosave()
@@ -3085,6 +3234,9 @@ func _build_ui() -> void:
 
 	_asset_browser.asset_selected_requested.connect(_on_asset_selected)
 	_asset_browser.selector_cancel_requested.connect(_on_selector_cancelled)
+	_asset_browser.plain_color_preview_requested.connect(_preview_plain_color)
+	_asset_browser.plain_color_commit_requested.connect(_commit_plain_color)
+	_asset_browser.plain_color_preview_cancel_requested.connect(_cancel_plain_color_preview)
 	_asset_browser.asset_load_failed.connect(func(kind: String, path: String) -> void:
 		if _scenery_repair_target != null and is_instance_valid(_scenery_repair_target):
 			_show_toast("Could not open that artwork. Try another file.")
@@ -3097,6 +3249,7 @@ func _build_ui() -> void:
 	_asset_browser.edit_scenery_requested.connect(_enter_scenery_edit_mode)
 	_asset_browser.surface_color_confirmed.connect(_record_recent_surface_color)
 	_asset_browser.set_surface_color_history(_recent_surface_colors)
+	_asset_browser.set_background_state(_background_kind, _sky_id, _plain_color)
 	_build_ground_finish_popup(ui)
 
 	_modal_views.build_file_dialogs(ui)
@@ -4510,6 +4663,8 @@ func _build_gizmo_layer() -> void:
 	_gizmos = STAGE_GIZMOS.new()
 	_gizmos.name = "GizmoLayer"
 	_gizmos.camera = _camera
+	if _sandbox_theme != null:
+		_gizmos.apply_theme(_sandbox_theme as SandboxTheme)
 	_gizmos.transform_committed.connect(_on_transform_committed)
 	_gizmos.transform_started.connect(_on_gizmo_transform_started)
 	_gizmos.transform_updated.connect(_on_gizmo_transform_updated)
@@ -4522,6 +4677,7 @@ func _build_grid_layer() -> void:
 	_grid.camera = _camera
 	add_child(_grid)
 	move_child(_grid, 0)
+	_update_grid_background_style()
 
 
 func _build_ghost_holder() -> void:
@@ -4542,15 +4698,19 @@ func _build_scenery_controller() -> void:
 
 func _build_sky_layer() -> void:
 	_sky_layer = CanvasLayer.new()
-	_sky_layer.name = "StageSkyLayer"
+	_sky_layer.name = "StageBackgroundLayer"
 	_sky_layer.layer = -1
-	_sky_view = STAGE_SKY_VIEW_SCRIPT.new() as StageSkyView
-	_sky_view.name = "StageSkyView"
-	_sky_view.set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
-	_sky_view.set_sky(_sky_id)
-	_sky_layer.add_child(_sky_view)
+	_background_view = STAGE_BACKGROUND_VIEW_SCRIPT.new() as StageBackgroundView
+	_background_view.name = "StageBackgroundView"
+	_background_view.set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
+	_background_view.set_background(_background_kind, _sky_id, _plain_color)
+	_sky_layer.add_child(_background_view)
 	add_child(_sky_layer)
-	_sky_view.bind_camera(_camera)
+	_background_view.bind_camera(_camera)
+	_sky_view = _background_view.get_sky_view()
+	if _sandbox_theme != null:
+		_background_view.apply_theme(_sandbox_theme as SandboxTheme)
+	_update_grid_background_style()
 
 
 func _build_placement_overlay() -> void:
@@ -4912,7 +5072,13 @@ func _open_selector(kind: String) -> void:
 		(_palette_buttons[pid] as Button).set_pressed_no_signal(pid == kind)
 	if kind == "scenery":
 		_asset_browser.set_surface_color_history(_recent_surface_colors)
-	var selector_state: Dictionary = _asset_browser.open_selector(kind, _spawner.get_selected_stickman_path(), _sky_id)
+	var selector_state: Dictionary = _asset_browser.open_selector(
+		kind,
+		_spawner.get_selected_stickman_path(),
+		_sky_id,
+		_background_kind,
+		_plain_color
+	)
 	if kind == "stickman":
 		var selected_stickman_path: String = String(selector_state.get("selected_stickman_path", _spawner.get_selected_stickman_path()))
 		if selected_stickman_path != _spawner.get_selected_stickman_path():
@@ -4940,12 +5106,14 @@ func _on_asset_selected(entry: Dictionary) -> void:
 			return
 		var background_kind: String = String(entry.get("background_kind", ""))
 		if background_kind == "sky":
-			_sky_id = StringName(String(entry.get("id", "sky_neutral")))
-			_sky_view.set_sky(_sky_id)
-			var scenery_selector: AssetSelector = _asset_browser.get_selector()
-			if scenery_selector != null:
-				scenery_selector.set_current_sky(_sky_id)
-			_mark_scene_dirty()
+			_commit_background_kind(&"sky", StringName(String(entry.get("id", "sky_neutral"))))
+			_refresh_scenery_capture_bar()
+			return
+		if background_kind == "plain":
+			_commit_background_kind(&"plain")
+			var plain_selector: AssetSelector = _asset_browser.get_selector()
+			if plain_selector != null:
+				plain_selector.open_plain_background_choices(_plain_color)
 			_refresh_scenery_capture_bar()
 			return
 		if background_kind == "wall":
@@ -5774,8 +5942,15 @@ func _handle_scenery_edit_motion(world_position: Vector2) -> void:
 
 
 func _close_selector() -> void:
+	var closing_kind: String = _selector_kind
+	_cancel_plain_color_preview()
 	if _asset_browser != null:
 		_asset_browser.close()
+	if closing_kind == "scenery":
+		# Scenery is a chooser entry; the capture bar communicates active drawing tools.
+		var scenery_button: Button = _palette_buttons.get("scenery") as Button
+		if scenery_button != null:
+			scenery_button.set_pressed_no_signal(false)
 
 
 func _on_selector_cancelled() -> void:
@@ -5783,7 +5958,7 @@ func _on_selector_cancelled() -> void:
 		return
 	var kind: String = _selector_kind
 	_close_selector()
-	if kind != "scenery" and kind != "starters":
+	if kind != "starters":
 		set_placement_mode("")
 
 
@@ -7900,8 +8075,12 @@ func _load_font(path: String) -> Font:
 	return _theme_controller.load_font(path)
 
 func _apply_theme_to_visuals() -> void:
-	if _sky_view != null and _sandbox_theme != null:
-		_sky_view.apply_theme(_sandbox_theme as SandboxTheme)
+	if _background_view != null and _sandbox_theme != null:
+		_background_view.apply_theme(_sandbox_theme as SandboxTheme)
+	if _grid != null:
+		_update_grid_background_style()
+	if _gizmos != null and _sandbox_theme != null:
+		_gizmos.apply_theme(_sandbox_theme as SandboxTheme)
 	if _director_visuals != null:
 		_director_visuals.set_style(_theme)
 		_director_visuals.completed_path_alpha = _sandbox_theme.number("overlays.completed_path_alpha", 0.20, 0.0, 1.0) if _sandbox_theme != null else 0.20

scripts/editors/stage/stage_asset_browser.gd

@@ -9,6 +9,9 @@ signal refresh_requested
 signal make_artwork_requested
 signal edit_scenery_requested
 signal surface_color_confirmed(color: Color)
+signal plain_color_preview_requested(color: Color)
+signal plain_color_commit_requested(color: Color)
+signal plain_color_preview_cancel_requested()
 
 const ASSET_SELECTOR_SCENE := preload("res://scenes/stage/asset_selector.tscn")
 const STICKMAN_LIBRARY_SCRIPT := preload("res://scripts/characters/stickman/stickman_library.gd")
@@ -32,6 +35,9 @@ var browse_dialog: FileDialog
 var thumbnail_queue: Array[Dictionary] = []
 var thumbnail_busy: bool = false
 var thumbnail_generation: int = 0
+var _current_background_kind: StringName = &"sky"
+var _current_sky_id: StringName = &"sky_neutral"
+var _current_plain_color: Color = Color("#F5EFE0")
 
 
 func _ready() -> void:
@@ -62,6 +68,10 @@ func build_ui(ui_layer: CanvasLayer, ui_font: Font, emoji_font: Font, sandbox_th
 	selector.make_artwork_requested.connect(func() -> void: make_artwork_requested.emit())
 	selector.edit_scenery_requested.connect(func() -> void: edit_scenery_requested.emit())
 	selector.surface_color_confirmed.connect(func(color: Color) -> void: surface_color_confirmed.emit(color))
+	selector.plain_color_preview_requested.connect(func(color: Color) -> void: plain_color_preview_requested.emit(color))
+	selector.plain_color_commit_requested.connect(func(color: Color) -> void: plain_color_commit_requested.emit(color))
+	selector.plain_color_preview_cancel_requested.connect(func() -> void: plain_color_preview_cancel_requested.emit())
+	selector.stage_preview_dimming_changed.connect(_on_selector_stage_preview_dimming_changed)
 	ui_layer.add_child(selector)
 	# apply_font AFTER add_child so the selector's @onready nodes resolve first.
 	selector.apply_font(ui_font, emoji_font)
@@ -92,12 +102,28 @@ func set_surface_color_history(colors: Array[Color]) -> void:
 		selector.set_surface_color_history(colors)
 
 
+func set_background_state(kind: StringName, sky_id: StringName, plain_color: Color) -> void:
+	_current_background_kind = &"plain" if kind == &"plain" else &"sky"
+	_current_sky_id = sky_id
+	_current_plain_color = Color(plain_color.r, plain_color.g, plain_color.b, 1.0)
+	if selector != null:
+		selector.set_background_state(_current_background_kind, _current_sky_id, _current_plain_color)
+
+
 func _starter_scene_entries() -> Array[Dictionary]:
 	return [
+		{
+			"id": "starter_plain_background",
+			"name": "Plain Background",
+			"description": "An empty stage with one color. Choose a new color whenever you like.",
+			"category": "Make your own",
+			"path": "res://content/stages/starters/plain_background.scene",
+			"icon": "🎨",
+		},
 		{
 			"id": "starter_blank_scene",
-			"name": "Blank Scene",
-			"description": "Start fresh with an open stage and a clear sky.",
+			"name": "Open Sky",
+			"description": "An empty stage with a soft sky. Sun and clouds, ready for your story.",
 			"category": "Make your own",
 			"path": "res://content/stages/starters/blank.scene",
 			"icon": "✨",
@@ -129,7 +155,16 @@ func make_browse_entry(kind: String, path: String) -> Dictionary:
 	return stickman_library.make_entry(path)
 
 
-func open_selector(kind: String, current_stickman_path: String, current_sky_id: StringName = &"") -> Dictionary:
+func open_selector(
+	kind: String,
+	current_stickman_path: String,
+	current_sky_id: StringName = &"",
+	background_kind: StringName = &"sky",
+	plain_color: Color = Color("#F5EFE0")
+) -> Dictionary:
+	_current_background_kind = &"plain" if background_kind == &"plain" else &"sky"
+	_current_sky_id = current_sky_id if not current_sky_id.is_empty() else &"sky_neutral"
+	_current_plain_color = Color(plain_color.r, plain_color.g, plain_color.b, 1.0)
 	set_selector_kind(kind)
 	var entries: Array[Dictionary] = scan_entries(kind)
 	if kind == "starters":
@@ -142,7 +177,7 @@ func open_selector(kind: String, current_stickman_path: String, current_sky_id:
 		selected_stickman_path = String(entries[0].get("path", ""))
 	var auto_selection: Dictionary = entries[0] if kind == "stickman" and entries.size() == 1 else {}
 	if auto_selection.is_empty():
-		open(kind, entries, current_sky_id)
+		open(kind, entries, _current_sky_id)
 	return {
 		"entries": entries,
 		"selected_stickman_path": selected_stickman_path,
@@ -152,6 +187,7 @@ func open_selector(kind: String, current_stickman_path: String, current_sky_id:
 
 func _scenery_background_entries() -> Array[Dictionary]:
 	return [
+		{"id": "plain_background", "name": "Plain Background", "category": "Scene background", "gallery_tab": "backgrounds", "background_kind": "plain", "plain_color": _current_plain_color, "icon": "🎨"},
 		{"id": "sky_clear_day", "name": "Clear Day", "category": "Sky", "gallery_tab": "backgrounds", "background_kind": "sky", "icon": "☀️"},
 		{"id": "sky_cloudy_day", "name": "Cloudy Day", "category": "Sky", "gallery_tab": "backgrounds", "background_kind": "sky", "icon": "☁️"},
 		{"id": "sky_sunset", "name": "Sunset", "category": "Sky", "gallery_tab": "backgrounds", "background_kind": "sky", "icon": "🌅"},
@@ -170,8 +206,9 @@ func open(kind: String, entries: Array[Dictionary], current_sky_id: StringName =
 	selector_open = true
 	if selector_dim != null:
 		selector_dim.visible = true
+		selector_dim.color = Color(0.0, 0.0, 0.0, SELECTOR_DIM_ALPHA)
 	if selector != null:
-		selector.open(kind, entries, String(current_sky_id))
+		selector.open(kind, entries, String(current_sky_id), String(_current_background_kind), _current_plain_color)
 	load_or_enqueue_thumbnails(kind, entries)
 
 
@@ -206,6 +243,8 @@ func set_entries(entries: Array[Dictionary]) -> void:
 
 func refresh_selector_entries() -> Array[Dictionary]:
 	var entries: Array[Dictionary] = scan_entries(selector_kind)
+	if selector_kind == "scenery":
+		entries.append_array(_scenery_background_entries())
 	set_entries(entries)
 	return entries
 
@@ -282,6 +321,13 @@ func _on_selector_cancelled() -> void:
 		selector_cancel_requested.emit()
 
 
+func _on_selector_stage_preview_dimming_changed(should_dim: bool) -> void:
+	if selector_dim == null:
+		return
+	selector_dim.color = Color(0.0, 0.0, 0.0, SELECTOR_DIM_ALPHA if should_dim else 0.0)
+	selector_dim.visible = selector_open
+
+
 func _on_selector_popup_hide() -> void:
 	if not selector_open:
 		return

scripts/editors/stage/stage_scene_adapter.gd

@@ -130,6 +130,8 @@ func collect(
 		"version": STAGE_SCENE_IO.FILE_VERSION,
 		"scene_name": scene_name,
 		"sky_id": String(document_metadata.get("sky_id", "sky_neutral")),
+		"background_kind": String(document_metadata.get("background_kind", "sky")),
+		"plain_color": String(document_metadata.get("plain_color", STAGE_SCENE_IO.DEFAULT_PLAIN_COLOR)),
 		"camera": {"position": STAGE_SCENE_IO.vector_to_data(camera_position), "zoom": camera_zoom},
 		"objects": objects,
 		"event_rules": rules_result["rules"],
@@ -299,6 +301,8 @@ func apply(data: Dictionary, world: Node2D, spawner: StageSpawner) -> Dictionary
 		"missing_paths": missing_paths,
 		"decoded_rules": decoded_rules,
 		"sky_id": String(data.get("sky_id", "sky_neutral")),
+		"background_kind": String(data.get("background_kind", "sky")),
+		"plain_color": String(data.get("plain_color", STAGE_SCENE_IO.DEFAULT_PLAIN_COLOR)),
 	}