QSplitter, XCB: Bad cursor shape after clicking on a widget

1. Compile and run the test application (on Linux/X11).
2. Move the mouse cursor over the line edit inside splitter (on the bottom-left).
3. Press the left mouse button - the cursor changes its shape.

This happens only when widget outside QSplitter is native window (the QLineEdit on the right) and widgets inside QSplitter are alien, and "Qt::AA_DontCreateNativeWidgetSiblings" flag is not set.
Works properly on Windows.