This patch modifies backspace behaviour when text is selected so that it doesn't delete the character preceding the selection.
diff 61f028fdacb96dddf66d5ff2edeefc530a00cb58 uncommitted
--- a/sys/src/cmd/rio/wind.c
+++ b/sys/src/cmd/rio/wind.c
@@ -892,16 +892,44 @@
 			return;
 		case Kleft:
 			if(w->q0 > 0){
-				q0 = w->q0-1;
-				wsetselect(w, q0, q0);
-				wshow(w, q0);
+				if(w->q1 != w->q0) {
+					q0 = w->q0;
+					wsetselect(w, q0, q0);
+					wshow(w, q0);
+				}
+				else {
+					q0 = w->q0-1;
+					wsetselect(w, q0, q0);
+					wshow(w, q0);
+				}
 			}
+			else {
+				if(w->q1 != w->q0) {
+					q0 = 0;
+					wsetselect(w, q0, q0);
+					wshow(w, q0);
+				}			
+			}
 			return;
 		case Kright:
 			if(w->q1 < w->nr){
-				q1 = w->q1+1;
-				wsetselect(w, q1, q1);
-				wshow(w, q1);
+				if(w->q1 != w->q0) {
+					q1 = w->q1;
+					wsetselect(w, q1, q1);
+					wshow(w, q1);
+				} 
+				else {
+					q1 = w->q1+1;
+					wsetselect(w, q1, q1);
+					wshow(w, q1);
+				}
+			}
+			else {
+				if(w->q1 != w->q0) {
+					q1 = w->nr;
+					wsetselect(w, q1, q1);
+					wshow(w, q1);
+				}			
 			}
 			return;
 		case Khome: