diff --git a/engine/app.cpp b/engine/app.cpp
index 6ebc4c8..dc7f78f 100644
--- a/engine/app.cpp
+++ b/engine/app.cpp
@@ -17,6 +17,7 @@ void android_async_unlock(struct engine* engine);
 void async_lock();
 void async_swap();
 void async_unlock();
+void destroy_window();
 #endif
 
 using namespace ui;
@@ -29,6 +30,30 @@ void App::create()
     height = 1080/2;
 }
 
+bool App::request_close()
+{
+    static bool dialog_already_opened = false;
+    if (ui::Canvas::I->m_unsaved && !dialog_already_opened)
+    {
+        async_start();
+        auto* m = layout[main_id]->add_child<NodeMessageBox>();
+        m->m_title->set_text("Unsaved document");
+        m->m_message->set_text("Would you like to save before closing?");
+        m->btn_ok->m_text->set_text("Yes");
+        m->btn_ok->on_click = [](Node*) {
+        };
+        m->btn_cancel->m_text->set_text("No");
+        m->btn_cancel->on_click = [](Node*) {
+            destroy_window();
+            PostQuitMessage(0);
+        };
+        async_redraw();
+        async_end();
+        dialog_already_opened = true;
+    }
+    return false;
+}
+
 void App::clear()
 {
     glClearColor(.1f, .1f, .1f, 1.f);
diff --git a/engine/app.h b/engine/app.h
index 9802493..f09ee6a 100644
--- a/engine/app.h
+++ b/engine/app.h
@@ -101,6 +101,7 @@ public:
     void initAssets();
     void initLayout();
     void create();
+    bool request_close();
     void terminate();
     void clear();
     void update(float dt);
diff --git a/engine/app_layout.cpp b/engine/app_layout.cpp
index ae14c6f..30cc77c 100644
--- a/engine/app_layout.cpp
+++ b/engine/app_layout.cpp
@@ -14,7 +14,7 @@ static glm::vec4 color_button_hlight{ 1, .0, .0, 1 };
 void App::title_update(std::string name, int resolution)
 {
     static char str[256];
-    snprintf(str, 256, "Panodoc: %s (%dpx)", doc_name.c_str(), resolution);
+    snprintf(str, 256, "Panodoc: %s%s (%dpx)", doc_name.c_str(), canvas->m_canvas->m_unsaved ? "*" : "", resolution);
     if (auto docname = layout[main_id]->find<NodeText>("txt-docname"))
         docname->set_text(str);
 }
@@ -661,6 +661,7 @@ void App::initLayout()
         layout[main_id]->add_child(butt);
 
         butt->on_click = [this](Node*){
+            toggle_ui();
         };
 
         if (auto* slider = layout[main_id]->find<NodeSliderH>("frames-slider"))
diff --git a/engine/brush.cpp b/engine/brush.cpp
index 48a1623..30dc9a0 100644
--- a/engine/brush.cpp
+++ b/engine/brush.cpp
@@ -145,7 +145,7 @@ ui::StrokeSample ui::Stroke::randomize_sample(const glm::vec2& pos, float pressu
     s.flow = m_brush.m_tip_flow * (1.f - rnd_nor() * m_brush.m_jitter_flow) * flow_dyn;
     auto hsv = convert_rgb2hsv(m_brush.m_tip_color);
     hsv.x = glm::clamp(glm::mix(hsv.x, (pressure - 0.5f) * 2.0f, m_brush.m_tip_hue * (float)m_brush.m_tip_hue_pressure) + (rnd_nor() - 0.5f) * m_brush.m_jitter_hue, 0.f, 1.f);
-    hsv.y = glm::clamp(glm::mix(hsv.y, (pressure - 0.5f) * 2.0f, m_brush.m_tip_sat * (float)m_brush.m_tip_sat_pressure) + (rnd_nor() - 0.5f) * m_brush.m_jitter_sat, 0.f, 1.f);
+    hsv.y = glm::clamp(glm::mix(hsv.y, (1.f - pressure - 0.5f) * 2.0f, m_brush.m_tip_sat * (float)m_brush.m_tip_sat_pressure) + (rnd_nor() - 0.5f) * m_brush.m_jitter_sat, 0.f, 1.f);
     hsv.z = glm::clamp(glm::mix(hsv.z, (pressure - 0.5f) * 2.0f, m_brush.m_tip_val * (float)m_brush.m_tip_val_pressure) + (rnd_nor() - 0.5f) * m_brush.m_jitter_val, 0.f, 1.f);
     m_hsv_jitter.add(hsv);
     s.col = convert_hsv2rgb(m_hsv_jitter.average());
diff --git a/engine/canvas.cpp b/engine/canvas.cpp
index 2782e94..d3faa59 100644
--- a/engine/canvas.cpp
+++ b/engine/canvas.cpp
@@ -462,6 +462,7 @@ void ui::Canvas::stroke_commit()
 {
     if (!m_dirty || m_layers.empty())
         return;
+    m_unsaved = true;
     m_dirty = false;
     m_dirty_stroke = true; // new stroke ready for timelapse capture
     App::I.redraw = true;
@@ -805,6 +806,7 @@ bool ui::Canvas::create(int width, int height)
     }
     m_smask.create(width*2, height*2, "mask");
     m_smask.clear({1, 1, 1, 1});
+    m_unsaved = true;
     return true;
 }
 
@@ -1452,6 +1454,7 @@ void ui::Canvas::project_save_thread(std::string file_path)
     pb->destroy();
     App::I.async_update();
     App::I.async_end();
+    m_unsaved = false;
 }
 
 void ui::Canvas::project_open(std::string file_path, std::function<void()> on_complete)
@@ -1597,6 +1600,7 @@ void ui::Canvas::project_open_thread(std::string file_path)
         gl.restore();
         App::I.async_end();
     }
+    m_unsaved = false;
 }
 
 ui::Image ui::Canvas::thumbnail_generate(int w, int h)
diff --git a/engine/canvas.h b/engine/canvas.h
index 61b69cc..25e73fb 100644
--- a/engine/canvas.h
+++ b/engine/canvas.h
@@ -48,6 +48,7 @@ public:
     Plane m_plane;
     Plane m_plane_brush;
     BrushMesh m_mesh;
+    bool m_unsaved = false;
     bool m_dirty = false;
     bool m_commit_delayed = false;
     bool m_dirty_stroke = false;
diff --git a/engine/main.cpp b/engine/main.cpp
index b608b07..c41d37b 100644
--- a/engine/main.cpp
+++ b/engine/main.cpp
@@ -47,6 +47,11 @@ std::string GetLastErrorAsString()
     return message;
 }
 
+void destroy_window()
+{
+    DestroyWindow(hWnd);
+}
+
 void async_lock()
 {
     //std::lock_guard<std::mutex> _lock(async_mutex);
@@ -456,7 +461,9 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wp, LPARAM lp)
         BT_SetTerminate();
         break;
     case WM_CLOSE:
-        PostQuitMessage(0);
+        if (App::I.request_close())
+            PostQuitMessage(0);
+        else return true;
         break;
     case WM_SIZE:
     {