flet-dev · FeodorFitsner · May 6, 2026 · May 5, 2026 · May 5, 2026 · May 5, 2026
diff --git a/.agents/skills/test-flet-apps-dev/SKILL.md b/.agents/skills/test-flet-apps-dev/SKILL.md
@@ -0,0 +1,152 @@
+---
+name: test-flet-apps-dev
+description: Use when testing or debugging Flet apps in maintainer/contributor development mode with local Python package sources and the local Flutter client, including web, desktop, browser, and computer-use verification workflows.
+---
+
+# Test Flet Apps In Dev Mode
+
+Use this skill when validating a Flet app, example, feature, or bug fix against
+this repo's local Python packages and/or local Flutter client during maintainer
+or contributor work.
+
+## Core model
+
+Flet dev-mode testing usually has one or two processes:
+
+1. A Python Flet app/server, run from `sdk/python`.
+2. The local Flutter client, run from `client`, when Dart/client or extension code
+   must be tested.
+
+If only Python code changed, `uv run flet run ...` is often enough. If Dart,
+Flutter, extension, or transport code changed, run the local Flutter client so
+the changed Dart code is actually used.
+
+The local Flutter client debug build uses a fixed app-server URL from
+`client/lib/main.dart`:
+
+```dart
+if (kDebugMode) {
+  pageUrl = "http://localhost:8550";
+}
+```
+
+Therefore, when using the local Flutter client without extra URL arguments,
+start the Python app on port `8550`.
+
+## Start the Python app
+
+Run from `{repo}/sdk/python`:
+
+```bash
+uv run flet run -w -p 8550 examples/controls/core/interactive_viewer/handling_events/main.py
+```
+
+Adjust the sample path as needed. Use port `8550` when the local Flutter client
+will connect with its default debug URL. Keep this process running and watch its
+stdout for Python callback output, tracebacks, and event payloads.
+
+For web-only checks with the packaged web client, open:
+
+```text
+http://127.0.0.1:8550
+```
+
+## Run the local Flutter client
+
+Run these from `{repo}/client`.
+
+### Desktop
+
+Use when validating native desktop behavior on the current host OS:
+
+```bash
+fvm flutter run -d macos     # macOS
+fvm flutter run -d windows   # Windows
+fvm flutter run -d linux     # Linux
+```
+
+The debug client defaults to `http://localhost:8550` when no app URL argument is
+provided. Use the platform target that exists on the current machine. Use
+Computer Use or the relevant platform automation to navigate and interact with
+the app window.
+
+### Flutter web in Chrome
+
+Use when Dart web behavior must be validated in Flutter's default web debug
+browser:
+
+```bash
+fvm flutter run -d chrome
+```
+
+This opens a fresh browser connected to the Python app server on port `8550`.
+
+### Flutter web in another Chromium browser
+
+If the requested browser is not listed by `flutter devices`, prefer the web
+server target and open the served URL in that browser:
+
+```bash
+fvm flutter run -d web-server --web-hostname 127.0.0.1 --web-port 8660
+open -a "Brave Browser" http://127.0.0.1:8660
+```
+
+Using `CHROME_EXECUTABLE` can work, but Flutter may fail to attach its debug
+websocket in non-default Chromium browsers. Fall back to `web-server` if that
+happens.
+
+## Browser and UI interaction
+
+- For local browser targets (`localhost`, `127.0.0.1`, `file://`), prefer the
+  in-app browser or the Browser Use plugin when explicitly requested.
+- Use Computer Use for native desktop apps and external browsers when browser
+  MCP is not the requested tool or cannot control that browser.
+- For chart/canvas-heavy UI, click/hover coordinates may be necessary because
+  accessibility trees often expose only the HTML canvas container.
+
+## Reading evidence
+
+Always inspect both sides:
+
+- Python app stdout: event payloads, user `print()` calls, Python tracebacks.
+- Flutter run stdout: client-side event payloads, WebSocket messages, Flutter
+  exceptions, hot reload/restart status.
+- Browser/app state: the actual rendered UI and any visible error banner.
+
+For client/server protocol bugs, compare the raw outgoing Dart event in Flutter
+logs with the decoded Python event object in Python logs.
+
+## Hot reload and restart
+
+For Flutter client sessions:
+
+- Press `r` for hot reload after many Dart-only edits.
+- Press `R` for hot restart if state, initialization, or extension registration
+  may be stale.
+- Quit with `q` before final response unless the user explicitly wants the app
+  left running.
+- Press `h` for help on other Flutter run key commands.
+
+For Python app sessions, restart `uv run flet run ...` after Python source or
+sample changes if the running process does not pick them up.
+
+## Troubleshooting
+
+- If a sandboxed Flutter command fails trying to write FVM or Flutter cache files
+  such as `engine.stamp`, rerun the same command with escalation.
+- If `flutter devices` does not list Brave/Edge/etc., use `flutter run -d web-server`
+  and open the URL in the target browser.
+- If the UI shows a generic Flet error banner, check Python stdout first; the
+  root cause is often a handler exception.
+- If an event handler indexes a list payload, confirm the empty-list case before
+  treating it as a framework bug.
+- If the local Flutter client cannot connect, confirm the Python app is running
+  on port `8550` or pass an explicit app URL when the client path supports it.
+
+## Finish checklist
+
+- Stop long-running app/test sessions unless asked to leave them running.
+- State exactly which surfaces were tested: packaged web, local Flutter web,
+  desktop target, target browser, or sample-only.
+- Include the key observed payload/error before and after the fix.
+- Separate framework bugs from sample-code guard issues.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -29,7 +29,9 @@
 * Fix `Page.on_resize` and `Page.on_media_change` not firing after mobile orientation changes ([#6457](https://github.com/flet-dev/flet/issues/6457), [#6423](https://github.com/flet-dev/flet/pull/6423)) by @ndonkoHenri.
 * Fix `flet pack` desktop packaging so Windows and Linux bundles include the expected client archive, and Windows taskbar pins point to the packed app instead of the cached `flet.exe` ([#5151](https://github.com/flet-dev/flet/issues/5151), [#6403](https://github.com/flet-dev/flet/pull/6403)) by @ndonkoHenri.
 * Fix environment variable priority in `flet build` template: inherit from `Platform.environment` and use `putIfAbsent` for FLET_* variables so pre-set system env vars are not overwritten ([#6394](https://github.com/flet-dev/flet/pull/6394)) by @Bahtya.
+* Fix `NavigationBarDestination.selected_icon` rendering wrongly when provided as an `Icon` control ([#6460](https://github.com/flet-dev/flet/issues/6460), [#6468](https://github.com/flet-dev/flet/pull/6468)) by @ndonkoHenri.
 * Fix 3- and 4-digit hex color shorthand (e.g. `#c00`, `#fc00`) rendering as invisible by expanding them to their full 6/8-digit forms ([#6419](https://github.com/flet-dev/flet/issues/6419), [#6421](https://github.com/flet-dev/flet/pull/6421)) by @ndonkoHenri.
+* Fix `LineChartEvent.spots` returning undecoded MessagePack extension values instead of `LineChartEventSpot` objects ([#6443](https://github.com/flet-dev/flet/issues/6443), [#6468](https://github.com/flet-dev/flet/pull/6468)) by @ndonkoHenri.
 * Fix `LineChart` (and other charts) silently dropping custom `ChartAxisLabel` entries whose `value` matched a tick only after floating-point rounding (e.g. `0.1`, `0.2`, `0.3`) by switching label lookup to a tolerance-based comparison scaled to the axis interval ([#6445](https://github.com/flet-dev/flet/issues/6445), [#6459](https://github.com/flet-dev/flet/pull/6459)) by @KangZhaoKui.
 
 ### Documentation

diff --git a/packages/flet/lib/src/controls/navigation_bar_destination.dart b/packages/flet/lib/src/controls/navigation_bar_destination.dart
@@ -2,7 +2,6 @@ import 'package:flutter/material.dart';
 
 import '../extensions/control.dart';
 import '../models/control.dart';
-import '../utils/icons.dart';
 import '../utils/numbers.dart';
 import 'base_controls.dart';
 
@@ -15,14 +14,13 @@ class NavigationBarDestinationControl extends StatelessWidget {
   Widget build(BuildContext context) {
     debugPrint("NavigationBarDestination build: ${control.id}");
 
-    var selectedIcon = control.getIconData("selected_icon");
     var child = NavigationDestination(
-        enabled: !control.disabled,
-        tooltip: !control.disabled ? control.getString("tooltip") : null,
-        icon: control.buildIconOrWidget("icon")!,
-        selectedIcon: control.buildWidget("selected_icon") ??
-            (selectedIcon != null ? Icon(selectedIcon) : null),
-        label: control.getString("label", "")!);
+      enabled: !control.disabled,
+      tooltip: !control.disabled ? control.getString("tooltip") : null,
+      icon: control.buildIconOrWidget("icon")!,
+      selectedIcon: control.buildIconOrWidget("selected_icon"),
+      label: control.getString("label", "")!,
+    );
 
     return BaseControl(control: control, child: child);
   }

diff --git a/sdk/python/packages/flet-charts/CHANGELOG.md b/sdk/python/packages/flet-charts/CHANGELOG.md
@@ -5,6 +5,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## 0.85.0
+
+### Fixed
+
+- Fixed `LineChartEvent.spots` returning undecoded MessagePack extension values instead of `LineChartEventSpot` objects ([#6443](https://github.com/flet-dev/flet/issues/6443), [#6468](https://github.com/flet-dev/flet/pull/6468)) by @ndonkoHenri.
+- Fixed `LineChart` (and other charts) silently dropping custom `ChartAxisLabel` entries whose `value` matched a tick only after floating-point rounding (e.g. `0.1`, `0.2`, `0.3`) by switching label lookup to a tolerance-based comparison scaled to the axis interval ([#6445](https://github.com/flet-dev/flet/issues/6445), [#6459](https://github.com/flet-dev/flet/pull/6459)) by @KangZhaoKui.
+
 ## 0.80.0
 
 Initial release.

diff --git a/sdk/python/packages/flet-charts/src/flet_charts/line_chart.py b/sdk/python/packages/flet-charts/src/flet_charts/line_chart.py
@@ -59,6 +59,10 @@ class LineChartEvent(ft.Event["LineChart"]):
     spots: list[LineChartEventSpot]
     """
     Spots on which the event occurred.
+
+    Note:
+        This list is empty when the event does not target a concrete point, for
+        example when the pointer hovers over or taps empty chart space.
     """
 
 

diff --git a/sdk/python/packages/flet-charts/src/flutter/flet_charts/lib/src/utils/line_chart.dart b/sdk/python/packages/flet-charts/src/flutter/flet_charts/lib/src/utils/line_chart.dart
@@ -25,7 +25,7 @@ class LineChartEventData extends Equatable {
 
   Map<String, dynamic> toMap() => <String, dynamic>{
         'type': eventType,
-        'spots': barSpots,
+        'spots': barSpots.map((spot) => spot.toMap()).toList(),
       };
 
   @override

diff --git a/.../flet/integration_tests/controls/material/golden/macos/navigation_bar/basic.png b/.../flet/integration_tests/controls/material/golden/macos/navigation_bar/basic.png
diff --git a/sdk/python/packages/flet/integration_tests/controls/material/test_navigation_bar.py b/sdk/python/packages/flet/integration_tests/controls/material/test_navigation_bar.py
@@ -16,15 +16,16 @@ async def test_basic(flet_app: ftt.FletTestApp, request):
     await flet_app.assert_control_screenshot(
         request.node.name,
         ft.NavigationBar(
+            selected_index=2,
             destinations=[
                 ft.NavigationBarDestination(icon=ft.Icons.EXPLORE, label="Explore"),
                 ft.NavigationBarDestination(icon=ft.Icons.COMMUTE, label="Commute"),
                 ft.NavigationBarDestination(
                     icon=ft.Icons.BOOKMARK_BORDER,
-                    selected_icon=ft.Icons.BOOKMARK,
+                    selected_icon=ft.Icon(ft.Icons.BOOKMARK),
                     label="Favorites",
                 ),
-            ]
+            ],
         ),
     )