Index: obj_arc_ui.c
===================================================================
--- obj_arc_ui.c	(revision 5282)
+++ obj_arc_ui.c	(revision 5283)
@@ -41,13 +41,34 @@
 	pcb_angle_t start = arc->StartAngle, delta = arc->Delta;
 
 	if (end_pt == NULL) {
-		fprintf(stderr, "Moving arc endpoint: start point not yet implemented %p\n", end_pt);
+		double end2, new_delta, new_start = atan2(-(ch->Y - arc->Y), (ch->X - arc->X)) * 180.0 / M_PI + 180.0;
+
+		end2 = start + delta;
+		new_delta = end2 - new_start;
+		if (new_delta > 360.0)
+			new_delta -= 360.0;
+		if (new_delta < -360.0)
+			new_delta += 360.0;
+
+/*		fprintf(stderr, "start: %f new_start: %f delta=%f new delta=%f\n", start, new_start, delta, new_delta);*/
+
+		if (delta > 0) {
+			if (new_delta < 0)
+				new_delta += 360.0;
+		}
+		else {
+			if (new_delta > 0)
+				new_delta -= 360.0;
+		}
+
+		start = new_start;
+		delta = new_delta;
 	}
 	else {
 		double new_delta, new_end = atan2(-(ch->Y - arc->Y), (ch->X - arc->X)) * 180.0 / M_PI + 180.0;
 		if (delta < 0)
 			new_end -= 360.0;
-		fprintf(stderr, "delta: %f abs-end: %f new-abs: %f new-delta: %f\n", delta, start+delta, new_end, new_end-start);
+/*		fprintf(stderr, "delta: %f abs-end: %f new-abs: %f new-delta: %f\n", delta, start+delta, new_end, new_end-start);*/
 		new_delta = new_end-start;
 		if (delta > 0) {
 			if (new_delta < 0)