diff --git a/interface/wx/appprog.h b/interface/wx/appprog.h
new file mode 100644
index 0000000000..eb65462e3c
--- /dev/null
+++ b/interface/wx/appprog.h
@@ -0,0 +1,55 @@
+/////////////////////////////////////////////////////////////////////////////
+// Name:        taskbarbutton.h
+// Purpose:     interface of wxAppProgressIndicator
+// Author:      wxWidgets team
+// Licence:     wxWindows licence
+/////////////////////////////////////////////////////////////////////////////
+
+/**
+    @class wxAppProgressIndicator
+
+    A helper class that can be used to update the progress bar in the taskbar button.
+
+    @library{wxcore}
+    @category{misc}
+
+    @onlyfor{wxmsw}
+
+    @see wxTaskBarButton
+    @since 3.1.0
+*/
+class WXDLLIMPEXP_CORE wxAppProgressIndicator
+{
+public:
+    /**
+        Constructs the wxAppProgressIndicator.
+
+        @param parent
+            The parent window of wxAppProgressIndicator. Note that the
+            window should has taskbar button showing. If parent is NULL,
+            the progress will reflect on the taskbar buttons of all the 
+            top level windows.
+        @param maxValue
+    */
+    wxAppProgressIndicator(wxWindow* parent = NULL, int maxValue = 100);
+    virtual ~wxAppProgressIndicator();
+
+    /**
+        Set the progress value in taskbar button of parent window.
+
+        @param value
+            The new value of the progress meter. It should be less than or equal
+            to the range.
+     */
+    void SetValue(int value);
+
+    /**
+        Set the progress range in taskbar button of parent window.
+     */
+    void SetRange(int range);
+
+    /**
+        Makes the progress bar run in indeterminate mode.
+    */
+    bool Pulse();
+};
diff --git a/interface/wx/taskbarbutton.h b/interface/wx/taskbarbutton.h
index f17c92c65a..18497de0f7 100644
--- a/interface/wx/taskbarbutton.h
+++ b/interface/wx/taskbarbutton.h
@@ -1,6 +1,6 @@
 /////////////////////////////////////////////////////////////////////////////
 // Name:        taskbarbutton.h
-// Purpose:     interface of wxTaskBarButton
+// Purpose:     Interface of taskbar buttons features.
 // Author:      wxWidgets team
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
@@ -331,53 +331,6 @@ public:
     virtual wxThumbBarButton* RemoveThumbBarButton(int id);
 };
 
-/**
-    @class wxAppProgressIndicator
-
-    A helper class that can be used to update the progress bar in the taskbar button.
-
-    @library{wxcore}
-    @category{misc}
-
-    @onlyfor{wxmsw}
-
-    @see wxTaskBarButton
-    @since 3.1.0
-*/
-class WXDLLIMPEXP_CORE wxAppProgressIndicator
-{
-public:
-    /**
-        Constructs the wxAppProgressIndicator.
-
-        @param parent
-            The parent window of wxAppProgressIndicator. Note that the
-            window should has taskbar button showing.
-        @param maxValue
-    */
-    wxAppProgressIndicator(wxWindow* parent, int maxValue);
-    virtual ~wxAppProgressIndicator();
-
-    /**
-        Set the progress value in taskbar button of parent window.
-
-        @param value
-            The new value of the progress meter. It should be less than or equal
-            to the range.
-     */
-    void SetValue(int value);
-
-    /**
-        Set the progress range in taskbar button of parent window.
-     */
-    void SetRange(int range);
-
-    /**
-        Makes the progress bar run in indeterminate mode.
-    */
-    bool Pulse();
-};
-
 /**
     Type of jump list item.