Double clicking seemed to work sometimes... but I had to double click on the different frameboxes and sometimes all of them did reset the zoom (but not always). You could also try right clicking on axis and using revert axis or revert scale.
Creating quick script / toolbar / add-in could also be an option
(Current Report() << XPath("//AxisBox")) << Revert Axis;
or
(Current Report() << XPath("//AxisBox")) << Revert Scale;
-Jarmo