Fixed: Incorrect assumption that mouse button is released when window is allocated

src/video/windows/SDL_windowsevents.c

@@ -374,7 +374,7 @@ WIN_CheckAsyncMouseRelease(SDL_WindowData *data)
     if (!(keyState & 0x8000)) {
         WIN_CheckWParamMouseButton(SDL_FALSE, mouseFlags, swapButtons, data, SDL_BUTTON_X2, 0);
     }
-    data->mouse_button_flags = 0;
+    data->mouse_button_flags = (WPARAM)-1;
 }
 
 static void

src/video/windows/SDL_windowswindow.c

@@ -188,7 +188,7 @@ SetupWindowData(_THIS, SDL_Window * window, HWND hwnd, HWND parent, SDL_bool cre
     data->hinstance = (HINSTANCE) GetWindowLongPtr(hwnd, GWLP_HINSTANCE);
     data->created = created;
     data->high_surrogate = 0;
-    data->mouse_button_flags = 0;
+    data->mouse_button_flags = (WPARAM)-1;
     data->last_pointer_update = (LPARAM)-1;
     data->videodata = videodata;
     data->initializing = SDL_TRUE;