Rescale to show all only rescaled the axis range of current layer in the past. In Origin 2018b, it will take care of linked overlapping layers. Usually Multy-Y plots have such linked overlapping layers. E.g. on one layer, data range is from 2000 to 2005. On the other layer, the data range is from 2001 to 2006. 

Registry based System variable @RML (Rescale Multiple Layers) 

1 – rescale multiple layers

0 - rescale active layer only (old behavior)