Square QwtPlotGrid

[drunknight]

Thanks for your attention,Uwe! We have fixed this this week with your little tip. However, with the program going , now we face another problem. I hope you can give me some advice too.
QQ截图20140514144741.png
This is what happened when I was dragging the plot canvas. The curves and grid can't show themselves automatically and simultaneously with the drag action, but right after it.
Would you help me with this?
Thanks again!