当我从剪贴板粘贴到外部程序时，为什么Qt程序会处理剪贴板数据？

我做了以下的事情：

1）在Windows上的Qt程序中将数据复制到剪贴板。

QApplication::clipboard()->setText(data); 

2）将数据粘贴到外部程序（notepad.exe）。 After that my program starts to process clipboard data. It calls Windows specific methods:

 QWindowsOleDataObject::GetData(...); ... QWindowsMimeText::convertFromMime(...); 

It is a problem, because when the size of data in clipboard is big my program fails on memory allocating in those methods.

I can't understand it because the call stack is quite strange:

 qwindowsd.dll!QWindowsMimeText::convertFromMime(const tagFORMATETC & formatetc, const QMimeData * mimeData, tagSTGMEDIUM * pmedium) Line 606 C++ qwindowsd.dll!QWindowsOleDataObject::GetData(tagFORMATETC * pformatetc, tagSTGMEDIUM * pmedium) Line 144 C++ [External Code] Qt5Cored.dll!QEventDispatcherWin32::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 740 C++ qwindowsd.dll!QWindowsGuiEventDispatcher::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 73 C++ Qt5Cored.dll!QEventLoop::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 129 C++ Qt5Cored.dll!QEventLoop::exec(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 204 C++ Qt5Cored.dll!QCoreApplication::exec() Line 1188 C++ Qt5Guid.dll!QGuiApplication::exec() Line 1508 C++ Qt5Widgetsd.dll!QApplication::exec() Line 2957 C++ main(int argc, char * * argv) Line 759 C++ 

It is some Qt internal work, I don't know how to impact on it.