Why there is an error message or not whether the gui option is resizable or proportional?

I made very simple gui with one axes, two pushbuttons, and one toolbar with data cursor.

Push button1 has callback function as below

ah=handles.axes1;

x1=1:10; y1=x1; x2=x1; y2=x1;

[AX,H1,H2]=plotyy(ah,x1,y1,x2,y2);

hold(AX(1),'off'); hold(AX(2),'off');

guidata(hObject,handles);

and push button2 has callback as below

function pushbutton2_Callback(hObject, eventdata, handles) % hObject handle to pushbutton2 (see GCBO) % eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)

ah=handles.axes1;

x1=1:11; y1=x1;

plot(ah,x1,y1);

hold(ah,'off');

guidata(hObject,handles);

When I use a gui option Non-resizable,

When I put a cursor,

I got huge error message as below,

Error using handle.handle/get Invalid or deleted object. Error in C:\Program Files\MATLAB\R2012b\toolbox\matlab\graph2d\plotyy.p>localUpdatePosition (line 373)

Error in C:\Program Files\MATLAB\R2012b\toolbox\matlab\graph2d\plotyy.p>@(obj,evd)(localUpdatePosition(obj,evd,ax(1),ax(2))) (line 212)

Warning: Error occurred while evaluating listener callback. > In graphics.datatip.datatip>localSetBestOrientation at 485 In graphics.datatip.datatip>localUpdatePositionFromDataCursor at 730 In graphics.datatip.datatip>localSetPosition at 645 In graphics.datatip.update>localZStacking at 95 In graphics.datatip.update at 33 In datacursormode>localWindowButtonDownFcnDatatip at 778 In datacursormode>localWindowButtonDownFcn at 617 In hgfeval at 63 In uitools.uimode.modeWindowButtonDownFcn at 108 In uitools.uimode.modeControl>localModeWindowButtonDownFcn at 151

Why this error happens with just simple gui?