6 files changed, 63 insertions, 7 deletions

diff --git a/LibGUI/GButton.cpp b/LibGUI/GButton.cpp
index cee19019d0..3fd616da0f 100644
--- a/LibGUI/GButton.cpp
+++ b/LibGUI/GButton.cpp
@@ -65,12 +65,24 @@ void GButton::paint_event(GPaintEvent&)
     }
 }
 
+void GButton::mousemove_event(GMouseEvent& event)
+{
+    if (m_tracking_cursor) {
+        bool being_pressed = rect().contains(event.position());
+        if (being_pressed != m_being_pressed) {
+            m_being_pressed = being_pressed;
+            update();
+        }
+    }
+    GWidget::mousemove_event(event);
+}
+
 void GButton::mousedown_event(GMouseEvent& event)
 {
     dbgprintf("Button::mouseDownEvent: x=%d, y=%d, button=%u\n", event.x(), event.y(), (unsigned)event.button());
-
     m_being_pressed = true;
-
+    m_tracking_cursor = true;
+    set_global_cursor_tracking(true);
     update();
     GWidget::mousedown_event(event);
 }
@@ -78,13 +90,15 @@ void GButton::mousedown_event(GMouseEvent& event)
 void GButton::mouseup_event(GMouseEvent& event)
 {
     dbgprintf("Button::mouseUpEvent: x=%d, y=%d, button=%u\n", event.x(), event.y(), (unsigned)event.button());
-
+    bool was_being_pressed = m_being_pressed;
     m_being_pressed = false;
-
+    m_tracking_cursor = false;
+    set_global_cursor_tracking(false);
     update();
     GWidget::mouseup_event(event);
-
-    if (on_click)
-        on_click(*this);
+    if (was_being_pressed) {
+        if (on_click)
+            on_click(*this);
+    }
 }
 
diff --git a/LibGUI/GButton.h b/LibGUI/GButton.h
index 606311aac0..b5164ca26e 100644
--- a/LibGUI/GButton.h
+++ b/LibGUI/GButton.h
@@ -18,10 +18,12 @@ private:
     virtual void paint_event(GPaintEvent&) override;
     virtual void mousedown_event(GMouseEvent&) override;
     virtual void mouseup_event(GMouseEvent&) override;
+    virtual void mousemove_event(GMouseEvent&) override;
 
     virtual const char* class_name() const override { return "GButton"; }
 
     String m_caption;
     bool m_being_pressed { false };
+    bool m_tracking_cursor { false };
 };
 
diff --git a/LibGUI/GWidget.cpp b/LibGUI/GWidget.cpp
index e2b77e33ec..8695fcda74 100644
--- a/LibGUI/GWidget.cpp
+++ b/LibGUI/GWidget.cpp
@@ -170,3 +170,19 @@ void GWidget::set_font(RetainPtr<Font>&& font)
     else
         m_font = move(font);
 }
+
+void GWidget::set_global_cursor_tracking(bool enabled)
+{
+    auto* win = window();
+    if (!win)
+        return;
+    win->set_global_cursor_tracking_widget(enabled ? this : nullptr);
+}
+
+bool GWidget::global_cursor_tracking() const
+{
+    auto* win = window();
+    if (!win)
+        return false;
+    return win->global_cursor_tracking_widget() == this;
+}
diff --git a/LibGUI/GWidget.h b/LibGUI/GWidget.h
index 15f3e1556c..afa10c370b 100644
--- a/LibGUI/GWidget.h
+++ b/LibGUI/GWidget.h
@@ -88,6 +88,9 @@ public:
     const Font& font() const { return *m_font; }
     void set_font(RetainPtr<Font>&&);
 
+    void set_global_cursor_tracking(bool);
+    bool global_cursor_tracking() const;
+
 private:
     GWindow* m_window { nullptr };
 
diff --git a/LibGUI/GWindow.cpp b/LibGUI/GWindow.cpp
index b6de4a7511..9aff94b40a 100644
--- a/LibGUI/GWindow.cpp
+++ b/LibGUI/GWindow.cpp
@@ -72,6 +72,13 @@ void GWindow::set_rect(const Rect& a_rect)
 void GWindow::event(GEvent& event)
 {
     if (event.is_mouse_event()) {
+        if (m_global_cursor_tracking_widget) {
+            // FIXME: This won't work for widgets-within-widgets.
+            auto& mouse_event = static_cast<GMouseEvent&>(event);
+            Point local_point { mouse_event.x() - m_global_cursor_tracking_widget->relative_rect().x(), mouse_event.y() - m_global_cursor_tracking_widget->relative_rect().y() };
+            auto local_event = make<GMouseEvent>(event.type(), local_point, mouse_event.buttons(), mouse_event.button());
+            m_global_cursor_tracking_widget->event(*local_event);
+        }
         if (!m_main_widget)
             return;
         auto& mouse_event = static_cast<GMouseEvent&>(event);
@@ -158,3 +165,11 @@ void GWindow::set_focused_widget(GWidget* widget)
         m_focused_widget->update();
     }
 }
+
+void GWindow::set_global_cursor_tracking_widget(GWidget* widget)
+{
+    if (widget == m_global_cursor_tracking_widget.ptr())
+        return;
+    m_global_cursor_tracking_widget = widget ? widget->makeWeakPtr() : nullptr;
+    gui_set_global_cursor_tracking_enabled(m_window_id, widget != nullptr);
+}
diff --git a/LibGUI/GWindow.h b/LibGUI/GWindow.h
index a958207f08..7a53e8a8db 100644
--- a/LibGUI/GWindow.h
+++ b/LibGUI/GWindow.h
@@ -4,6 +4,7 @@
 #include <SharedGraphics/Rect.h>
 #include <SharedGraphics/GraphicsBitmap.h>
 #include <AK/AKString.h>
+#include <AK/WeakPtr.h>
 
 class GWidget;
 
@@ -48,11 +49,16 @@ public:
 
     void update(const Rect& = Rect());
 
+    void set_global_cursor_tracking_widget(GWidget*);
+    GWidget* global_cursor_tracking_widget() { return m_global_cursor_tracking_widget.ptr(); }
+    const GWidget* global_cursor_tracking_widget() const { return m_global_cursor_tracking_widget.ptr(); }
+
 private:
     RetainPtr<GraphicsBitmap> m_backing;
     int m_window_id { -1 };
     bool m_is_active { false };
     GWidget* m_main_widget { nullptr };
     GWidget* m_focused_widget { nullptr };
+    WeakPtr<GWidget> m_global_cursor_tracking_widget;
 };