uipanels don't have their own HWND. If you use a utility such as Spy++ (which is bundled with Microsoft Visual Studio) or Winspector, you will see that there are very few actual window handles. Of these, you can get access to two:
1. Top-level window frame (SunAwtFrame) HWND -
jFrame = get(handle(hFig), 'JavaFrame');
HWND = jFrame.fFigureClient.getWindow.getHWND;
2. Axis canvas (SunAwtCanvas) HWND - this is the NativeWindowHandle property value that you have noted above. (there are several alternatives of accessing this handle). If you use this handle, be sure to check the corresponding NativeWindowHandleValid property. For example, if the window is not visible (e.g., closed), this property will have a false value.
3. OpenGL (MatlabOpenGLWindow) HWND - this is a child of the NativeWindowHandle HWND, and can be gotten from:
jFrame = get(handle(hFig), 'JavaFrame');
HWND = int32(jFrame.getNativeChildWindowHandle/2^32);
HWND = bitshift(jFrame.getNativeChildWindowHandle,-32);
Yair Altman
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