If activated (Edit -> Map Parameters -> Dynamic Map Sampling) the map will be re-sampled on a more coarse grid when the view is zoomed out. If “Display Size” is also activated, the box of electron density will be increased in size also. In this way, you can see electron density for big maps (many unit cells) and the graphics still remain rotatable.
If you want to have these functions active for all maps, add the following to your initialization file Scheme:
(set-dynamic-map-sampling-on)
(set-dynamic-map-size-display-on)