[BUG] Maxmizing or minimizing window crash

[bolin12]

#include "PainterEngine.h"

PX_OBJECT_EVENT_FUNCTION(OnButtonClick)
{
    PX_Object_PushButtonSetText(pObject, "我被点击了");
}

int main()
{
    PX_Object* myButtonObject;
    PainterEngine_Initialize(800, 480);
    PainterEngine_LoadFontModule("font.ttf", PX_FONTMODULE_CODEPAGE_GBK, 20);
    myButtonObject = PX_Object_PushButtonCreate(mp, root, 300, 200, 200, 80, "我是一个按钮", PainterEngine_GetFontModule());
    PX_ObjectRegisterEvent(myButtonObject, PX_OBJECT_EVENT_EXECUTE, OnButtonClick, 0);

    return 1;
}