diff --git a/tek4010 b/tek4010
index fa85911..1ff160d 100755
Binary files a/tek4010 and b/tek4010 differ
diff --git a/tek4010.c b/tek4010.c
index 95718f6..e4be4d0 100644
--- a/tek4010.c
+++ b/tek4010.c
@@ -363,7 +363,7 @@ void tek4010_draw(cairo_t *cr, cairo_t *cr2, int width, int height, int first)
                                         if (DEBUG) printf("***** Moving to (%d,%d)\n",x0,y0);
                                 break;
                         case 5: if (ch == 29) mode = 1;
-                                else {
+                                else if (tag != 0) {
                                         yh = 32 * (ch & 31);          mode++;
                                 }
                                 break;
diff --git a/tek4010.h b/tek4010.h
index 19f4c57..7474ba9 100644
--- a/tek4010.h
+++ b/tek4010.h
@@ -1,6 +1,6 @@
 
 #define WINDOW_WIDTH    1024                // proposed width of main window
-#define WINDOW_HEIGHT    780                // proposed height of main window
+#define WINDOW_HEIGHT    768                // proposed height of main window (as per Tektronix manual)
 #define WINDOW_NAME     "Tektronix 4010"    // name of main window
 #define ICON_NAME       ""                  // path to icon for window