Sample editor not selecting

Hope this is not old news. I’ve just finished a project that I bypassed any sample editing beyond basic splitting in the arrangement window because when double clicking a region it didn’t behave as described in the manual for me. When I double click on a selected region it opens the editor but shows the entire waveform it came from along with the entire waveform in the upper gray area. Thus, I have to find that smaller region I split and selected in the main window all over again in the editor in order to manipulate, sort of defeating the purpose of why I selected that certain region in the first place. Is this a bug? Am I missing something basic? A setting? Any help much appreciated. Thanks