Automatic Box Selection requires holding the mouse button instead of 2 mouse clicks

Draftsight is suddenly requiring me to hold the left mouse button to drag out a window during automatic box selection.  For all the years that I've used it, it has always been one click to select the starting point, then a second click to select the opposite box corner.  I much preferred  the 2-click method.  I can't find any setting that would change this.  Is there a way to get the 2-click method back?