Fix wxToggleButton image when state is changed programmatically

See #18779

include/wx/gtk/anybutton.h

@@ -45,15 +45,15 @@ protected:
     virtual void DoSetBitmap(const wxBitmap& bitmap, State which) wxOVERRIDE;
     virtual void DoSetBitmapPosition(wxDirection dir) wxOVERRIDE;
 
+    // update the bitmap to correspond to the current button state
+    void GTKUpdateBitmap();
+
 private:
     typedef wxAnyButtonBase base_type;
 
     // focus event handler: calls GTKUpdateBitmap()
     void GTKOnFocus(wxFocusEvent& event);
 
-    // update the bitmap to correspond to the current button state
-    void GTKUpdateBitmap();
-
     // return the state whose bitmap is being currently shown (so this is
     // different from the real current state, e.g. it could be State_Normal
     // even if the button is pressed if no button was set for State_Pressed)

src/gtk/tglbtn.cpp

@@ -148,6 +148,7 @@ void wxToggleButton::SetValue(bool state)
     wxGtkEventsDisabler<wxToggleButton> noEvents(this);
 
     gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(m_widget), state);
+    GTKUpdateBitmap();
 }
 
 // bool GetValue() const