diff --git a/Makefile b/Makefile
index c5371df..2faf1af 100644
--- a/Makefile
+++ b/Makefile
@@ -120,7 +120,7 @@ CSRC = $(STARTUPSRC) \
        $(SHELLSRC) \
        $(DSPLIBSRC) \
        usbcfg.c \
-       main.c si5351.c si5351_low.c tlv320aic3204.c dsp.c plot.c ili9431.c numfont20x24.c Font5x7.c flash.c
+       main.c si5351.c si5351_low.c tlv320aic3204.c dsp.c plot.c ui.c ili9431.c numfont20x24.c Font5x7.c flash.c
 
 #       $(TESTSRC) \
 
diff --git a/main.c b/main.c
index 230743a..7c7a00b 100644
--- a/main.c
+++ b/main.c
@@ -67,6 +67,7 @@ static THD_FUNCTION(Thread1, arg)
       chMtxLock(&mutex);
       scan_lcd();
       chMtxUnlock(&mutex);
+      ui_process();
 #endif
     }
 }
@@ -1104,16 +1105,16 @@ int main(void)
 
     //set_frequency(10000000);
 
-    while (1)
-    {
-    if (SDU1.config->usbp->state == USB_ACTIVE) {
-      //palSetPad(GPIOC, GPIOC_LED);
-      thread_t *shelltp = chThdCreateFromHeap(NULL, SHELL_WA_SIZE,
-                                              "shell", NORMALPRIO + 1,
-                                              shellThread, (void *)&shell_cfg1);
-      chThdWait(shelltp);               /* Waiting termination.             */
-      //palClearPad(GPIOC, GPIOC_LED);
-    }
-	chThdSleepMilliseconds(1000);
+    while (1) {
+      if (SDU1.config->usbp->state == USB_ACTIVE) {
+        //palSetPad(GPIOC, GPIOC_LED);
+        thread_t *shelltp = chThdCreateFromHeap(NULL, SHELL_WA_SIZE,
+                                                "shell", NORMALPRIO + 1,
+                                                shellThread, (void *)&shell_cfg1);
+        chThdWait(shelltp);               /* Waiting termination.             */
+        //palClearPad(GPIOC, GPIOC_LED);
+      }
+
+      chThdSleepMilliseconds(1000);
     }
 }
diff --git a/nanovna.h b/nanovna.h
index 2bce821..447f8b0 100644
--- a/nanovna.h
+++ b/nanovna.h
@@ -1,4 +1,7 @@
 
+/*
+ * tlv320aic3204.c
+ */
 extern void I2CWrite(int addr, uint8_t d0, uint8_t d1);
 
 typedef struct {
@@ -19,9 +22,16 @@ extern void tlv320aic3204_select_in1(void);
 extern void tlv320aic3204_select_in3(void);
 extern void tlv320aic3204_adc_filter_enable(int enable);
 
+
+/*
+ * ui.c
+ */
 extern void ui_init(void);
 extern void ui_process(void);
 
+/*
+ * dsp.c
+ */
 // 5ms @ 48kHz
 #define AUDIO_BUFFER_LEN 96
 
@@ -45,6 +55,9 @@ int si5351_set_frequency_with_offset(int freq, int offset, uint8_t drive_strengt
 
 #define RGB565(b,r,g)     ( (((b)<<8)&0xfc00) | (((r)<<2)&0x03e0) | (((g)>>3)&0x001f) )
 
+/*
+ * ili9341.c
+ */
 extern uint16_t spi_buffer[1024];
 
 void ili9341_init(void);
@@ -54,12 +67,15 @@ void ili9341_fill(int x, int y, int w, int h, int color);
 void ili9341_drawchar_5x7(uint8_t ch, int x, int y, uint16_t fg, uint16_t bg);
 void ili9341_drawstring_5x7(char *str, int x, int y, uint16_t fg, uint16_t bg);
 
+/*
+ * plot.c
+ */
 void plot_init(void);
-
-
 void set_sweep(int32_t start, int stop);
 void redraw(void);
 
+
+
 #define TRACES_MAX 4
 
 enum {
@@ -141,6 +157,9 @@ typedef struct {
   int32_t checksum;
 } config_t;
 
+/*
+ * flash.c
+ */
 #define CONFIG_MAGIC 0x436f4e45 /* 'CoNF' */
 
 extern config_t *active;
diff --git a/plot.c b/plot.c
index b7eb858..db17293 100644
--- a/plot.c
+++ b/plot.c
@@ -12,9 +12,6 @@ void draw_frequencies(void);
 static inline void force_set_markmap(void);
 void frequency_string(char *buf, size_t len, uint32_t freq);
 
-uint16_t markmap[2][8];
-uint16_t current_mappage = 0;
-
 #define OFFSETX 15
 #define OFFSETY 0
 #define WIDTH 291
@@ -31,6 +28,9 @@ trace_t trace[TRACES_MAX] = {
 };
 
 
+#define CELLWIDTH 32
+#define CELLHEIGHT 32
+
 /*
  * CELL_X0[27:31] cell position
  * CELL_Y0[22:26]
@@ -53,8 +53,17 @@ uint32_t trace_index[TRACES_MAX][101];
 
 #define CELL_P(i, x, y) (((((x)&0x03e0UL)<<22) | (((y)&0x03e0UL)<<17)) == ((i)&0xffc00000UL))
 
-#define CELLWIDTH 32
-#define CELLHEIGHT 32
+/* indicate dirty cells */
+uint16_t markmap[2][8];
+uint16_t current_mappage = 0;
+
+
+marker_t markers[4] = {
+  { 1, 30 }, { 0, 40 }, { 0, 60 }, { 0, 80 }
+};
+
+int active_marker = 0;
+
 
 
 int32_t fstart = 0;
@@ -64,7 +73,6 @@ int32_t fgrid = 50000000;
 int grid_offset;
 int grid_width;
 
-
 void set_sweep(int32_t start, int stop)
 {
   int32_t gdigit = 100000000;
@@ -105,6 +113,11 @@ circle_inout(int x, int y, int r)
   return 0;
 }
 
+
+#define POLAR_CENTER_X 146
+#define POLAR_CENTER_Y 116
+#define POLAR_RADIUS 116
+
 int
 smith_grid(int x, int y)
 {
@@ -194,22 +207,33 @@ draw_on_strut(int v0, int d, int color)
 }
 
 
-
+/*
+ * calculate log10(abs(gamma))
+ */ 
 float logmag(float *v)
 {
   return log10f(v[0]*v[0] + v[1]*v[1]);
 }
 
+/*
+ * calculate phase[-2:2] of coefficient
+ */ 
 float phase(float *v)
 {
   return 2 * atan2f(v[1], v[0]) / M_PI;
 }
 
+/*
+ * calculate abs(gamma) * 8
+ */ 
 float linear(float *v)
 {
   return - sqrtf(v[0]*v[0] + v[1]*v[1]) * 8;
 }
 
+/*
+ * calculate vswr; (1+gamma)/(1-gamma)
+ */ 
 float swr(float *v)
 {
   float x = sqrtf(v[0]*v[0] + v[1]*v[1]);
@@ -394,6 +418,8 @@ mark_cells_from_index(void)
   int t;
   /* mark cells between each neighber points */
   for (t = 0; t < TRACES_MAX; t++) {
+    if (!trace[t].enabled)
+      continue;
     int x0 = CELL_X(trace_index[t][0]);
     int y0 = CELL_Y(trace_index[t][0]);
     int m0 = x0 >> 5;
@@ -595,12 +621,6 @@ draw_marker(int w, int h, int x, int y, int c, int ch)
   }
 }
 
-marker_t markers[4] = {
-  { 1, 30 }, { 0, 40 }, { 0, 60 }, { 0, 80 }
-};
-
-int active_marker = 0;
-
 void
 cell_draw_markers(int m, int n, int w, int h)
 {