I got a similar problem.

With help of the realtime_plot example I created a scroll- and zoomable QwtPlot.

I attached yLeft/xBottom to one Zoomer and created another one for yRight/XTop.
After dissabling the Tracker and the RubberBand for the second Zoomer everything is working fine.

But now I got 4 scrollbars, moving either the one or the other curve seperatly. Would it somehow be possible to synchronize those Scrollbars, so that zooming and scrolling both curves synchron (like zooming and scrolling the canvas they're on)

Thanks for your help in advance!