diff --git a/src/callback.c b/src/callback.c
index 256cfe57..86044b7b 100644
--- a/src/callback.c
+++ b/src/callback.c
@@ -429,11 +429,11 @@ static int waves_callback(int event, int mx, int my, KeySym key, int button, int
           int idx;
           double cursorx;
           idx = get_raw_index(find_nth(get_tok_value(r->prop_ptr, "sweep", 0), ", ", "\"", 0, 1), NULL);
-          if(idx < 0) idx = 0;
           cursorx = xctx->graph_cursor1_x;
-          if(idx) {
+          if(idx >= 0 ) {
             cursorx = xctx->raw->cursor_a_val[idx];
           }
+          if(idx < 0) idx = 0;
           /* dragging cursors when mouse is very close */
           if( fabs(xctx->mousex - W_X(cursorx)) < 10) {
             xctx->graph_flags |= 16; /* Start move cursor1 */
@@ -443,11 +443,11 @@ static int waves_callback(int event, int mx, int my, KeySym key, int button, int
           int idx;
           double cursorx;
           idx = get_raw_index(find_nth(get_tok_value(r->prop_ptr, "sweep", 0), ", ", "\"", 0, 1), NULL);
-          if(idx < 0) idx = 0;
           cursorx = xctx->graph_cursor2_x;
-          if(idx) {
+          if(idx >= 0) {
             cursorx = xctx->raw->cursor_b_val[idx];
           }
+          if(idx < 0) idx = 0;
           /* dragging cursors when mouse is very close */
           if(fabs(xctx->mousex - W_X(cursorx)) < 10) {
             xctx->graph_flags |= 32; /* Start move cursor2 */
diff --git a/src/draw.c b/src/draw.c
index 78afbeef..eb01ca2f 100644
--- a/src/draw.c
+++ b/src/draw.c
@@ -2920,8 +2920,7 @@ static void draw_cursor(int active_cursor, int cursor_color, int i, Graph_ctx *g
     other_cursorx = xctx->graph_cursor1_x;
   }
   idx = get_raw_index(find_nth(get_tok_value(r->prop_ptr, "sweep", 0), ", ", "\"", 0, 1), NULL);
-  if(idx < 0) idx = 0;
-  if(idx) {
+  if(idx >= 0) {
     dbg(1, "draw_cursor(): idx=%d, cursor=%g\n", idx, xctx->raw->cursor_a_val[idx]);
     if(active_cursor == 1) {
       active_cursorx = xctx->raw->cursor_a_val[idx];
@@ -2931,6 +2930,7 @@ static void draw_cursor(int active_cursor, int cursor_color, int i, Graph_ctx *g
       other_cursorx = xctx->raw->cursor_a_val[idx];
     }
   }
+  if(idx < 0) idx = 0;
   xx = W_X(active_cursorx);
   flip = (other_cursorx > active_cursorx) ? 0 : 1;
   xoffs = flip ? 3 : -3;