When adding a new layer (shapefile) to a currently configured map, the map always zooms out to cover the extend of the newly added layer (shapefile). I often have my map zoomed in and set to a specific area of interest and then after I add the new layer (shapefile) I have to reposition map. There should be a setting to not reposition the map when adding a new layer (shapefile).
I would prefer zooming to all shapes in the layer to be an option you could set in the settings. So you could choose either (1) the current zoom methodology; (2) Don't change the extent at all; or (3) zoom to all the shapes in the new layer. Many times I know what the layer is I'm adding and don't need to see all the shapes.
Additionally, imo, if you instead zoom into the map so as to show all the shapes in the new layer, that would be even better.