error closing guide gui after snapshot

i am getting this error while click on red cross button of gui to close it after taking snapshot?

Invalid or deleted object.

Error in matlab.webcam.internal.PreviewController/closePreview

Error in matlab.webcam.internal.PreviewController/closePreviewWindowCallback

Error in
matlab.webcam.internal.PreviewController>@(src,event)obj.closePreviewWindowCallback 
Error while evaluating Figure CloseRequestFcn.
%% code of capture button
global cam;
img = snapshot(cam);
axes(handles.axes1);
imshow(img);
closePreview(cam);
delete (cam);
clear cam;
guidata(hObject, handles);

[Luciano Di iorio]

I have the same problem.. Do you have solution?

Im working with Matlab R2017a

While webcam is playing I cant close from red cross, but with a specific button for close the GUI yes