diff --git a/plot.c b/plot.c
index c5888e0..7239f09 100644
--- a/plot.c
+++ b/plot.c
@@ -30,8 +30,7 @@
 
 #ifdef __SCROLL__
 uint16_t _grid_y = NOSCROLL_GRIDY;
-int waterfall = false;
-int fullscreen = true;
+static int waterfall = false;
 #endif
 static void cell_draw_marker_info(int x0, int y0);
 static void cell_grid_line_info(int x0, int y0);
@@ -2290,7 +2289,6 @@ toggle_waterfall(void)
     _grid_y = SCROLL_GRIDY;
     ili9341_fill(OFFSETX, HEIGHT_SCROLL, LCD_WIDTH - OFFSETX, HEIGHT_NOSCROLL - HEIGHT_SCROLL, 0);
     waterfall = true;
-    fullscreen = false;
     w_min = (int)min_level;
     w_max = (int)peakLevel;
     if (w_max < w_min + 20)
@@ -2299,7 +2297,6 @@ toggle_waterfall(void)
   } else {
     _grid_y = NOSCROLL_GRIDY;
     waterfall = false;
-    fullscreen = true;
   }
   request_to_redraw_grid();
 }
diff --git a/sa_core.c b/sa_core.c
index 86d51e6..96e2f6d 100644
--- a/sa_core.c
+++ b/sa_core.c
@@ -1496,20 +1496,15 @@ pureRSSI_t perform(bool break_on_operation, int i, uint32_t f, int tracking)
   pureRSSI_t RSSI = float_TO_PURE_RSSI(-150);
   int t = 0;
   do {
-    int offs = 0,sm;
-    uint32_t lf = (uint32_t)f;
-    if (vbwSteps > 1) {         // Calculate sub steps
+    uint32_t lf = f;
+    if (vbwSteps > 1) {          // Calculate sub steps
+      int offs_div10 = (t - (vbwSteps >> 1)) * 500 / 10; // steps of half the rbw
+      if ((vbwSteps & 1) == 0)                           // Uneven steps, center
+        offs_div10+= 250 / 10;                           // Even, shift half step
+      int offs = offs_div10 * actual_rbw_x10;
       if (setting.step_delay_mode == SD_PRECISE)
-        sm = 250; // steps of a quarter rbw
-      else
-        sm = 500; // steps of half the rbw
-      if (vbwSteps & 1) { // Uneven steps, center
-        offs = (t - (vbwSteps >> 1)) * sm;
-      } else {            // Even, shift half step
-        offs = (t - (vbwSteps >> 1)) * sm + sm/2;
-      }
-      offs = (int)(offs * actual_rbw_x10/10.0);
-      lf = (uint32_t)(f + offs);
+        offs>>=1;                                        // steps of a quarter rbw
+      lf += offs;
     }
 
     // --------------- Set all the LO's ------------------------
@@ -1523,12 +1518,8 @@ pureRSSI_t perform(bool break_on_operation, int i, uint32_t f, int tracking)
     if (MODE_HIGH(setting.mode))
       local_IF = 0;
     else {
-      if (setting.auto_IF) {
-        if (setting.spur)
-          local_IF = 433900000;
-        else
-          local_IF = 433800000;
-      }
+      if (setting.auto_IF)
+        local_IF = setting.spur ? 433900000 : 433800000;
       else
         local_IF = setting.frequency_IF;
     }
diff --git a/ui.c b/ui.c
index 3f66690..d47d453 100644
--- a/ui.c
+++ b/ui.c
@@ -1771,6 +1771,9 @@ leave_ui_mode()
 //    request_to_draw_cells_behind_numeric_input();
 //    erase_numeric_input();
 //  }
+  // Erase bottom area (not redraw on area update)
+  if (MENU_BUTTON_HEIGHT*MENU_BUTTON_MAX - area_height > 0)
+    ili9341_fill(LCD_WIDTH-MENU_BUTTON_WIDTH, area_height, MENU_BUTTON_WIDTH, MENU_BUTTON_HEIGHT*MENU_BUTTON_MAX - area_height, DEFAULT_BG_COLOR);
   redraw_request|=REDRAW_AREA | REDRAW_FREQUENCY | REDRAW_CAL_STATUS | REDRAW_BATTERY;
 }
 
@@ -1927,10 +1930,9 @@ ui_mode_normal(void)
 {
   if (ui_mode == UI_NORMAL)
     return;
-
+  leave_ui_mode();
   area_width  = AREA_WIDTH_NORMAL;
   area_height = AREA_HEIGHT_NORMAL;
-  leave_ui_mode();
   ui_mode = UI_NORMAL;
 }