diff --git a/src/editor.c b/src/editor.c
index ccf6efa1..c99f095a 100644
--- a/src/editor.c
+++ b/src/editor.c
@@ -23,6 +23,7 @@
 
 #define ED_SIDEBAR_WIDTH        400
 #define ED_SPACING              10
+#define ED_MARGIN               20
 
 #define ED_MENU_HEIGHT          ((float)glwImLineHeight(win))
 
@@ -34,6 +35,9 @@
 
 #define ED_BONE_COLOR           0xffff00
 
+#define ED_MIN_BALL_RADIUS      0.1
+#define ED_MAX_BALL_RADIUS      30
+
 typedef struct editor {
   glwWin *win;
   float cameraAngleX;
@@ -54,6 +58,7 @@ typedef struct editor {
   int moveMouseY;
   bmesh *bm;
   skeleton *skl;
+  float ballRadius;
 } editor;
 
 #include "../data/bmesh_test_2.h"
@@ -145,6 +150,13 @@ static void display(glwWin *win) {
     glwImTabBox(win, GEN_ID, ED_SPACING / 2, ED_TOPBAR_HEIGHT, ED_SIDEBAR_WIDTH,
       ed->height - ED_TOPBAR_HEIGHT - ED_SPACING / 2,
       titles, icons, 0);
+    ed->ballRadius = glwImSlider(win, GEN_ID, glwImNextX(win) + ED_MARGIN,
+      glwImNextY(win) + ED_MARGIN,
+      ED_SIDEBAR_WIDTH - ED_MARGIN * 2,
+      ED_MIN_BALL_RADIUS, ED_MAX_BALL_RADIUS,
+      ed->ballRadius,
+      "Radius: %.4f",
+      ed->ballRadius);
   }
   
   {
diff --git a/src/glw.c b/src/glw.c
index efcde223..dcb5f939 100644
--- a/src/glw.c
+++ b/src/glw.c
@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <math.h>
+#include <stdarg.h>
 #include <CoreFoundation/CoreFoundation.h>
 #include "glw_internal.h"
 #include "glw_style.h"
@@ -102,8 +103,8 @@ void glwMouseEvent(glwWin *win, int button, int state, int x, int y) {
 
 int glwPointTest(int x, int y, int left, int top, int width, int height,
     int allowOffset) {
-  int right = left + width - 1 + allowOffset;
-  int bottom = top + height - 1 + allowOffset;
+  int right = left + width + allowOffset;
+  int bottom = top + height + 5 + allowOffset;
   left -= allowOffset;
   top -= allowOffset;
   return x >= left && x <= right && y >= top && y <= bottom;
@@ -903,3 +904,58 @@ int glwImMenu(glwWin *win, int id, int x, int y, int width, int height,
   imGUI->nextY = y + height;
   return sel;
 }
+
+static void glwDrawGradientLine(int x, int y, int width, int height,
+    unsigned int beginColor, unsigned int endColor) {
+  glLineWidth(height);
+  glBegin(GL_LINES);
+    glColor3f(glwR(beginColor), glwG(beginColor), glwB(beginColor));
+    glVertex2f(x, y);
+    glColor3f(glwR(endColor), glwG(endColor), glwB(endColor));
+    glVertex2f(x + width, y);
+  glEnd();
+  glLineWidth(1);
+}
+
+float glwImSlider(glwWin *win, int id, int x, int y, int width,
+    float min, float max, float cur, char *fmt, ...) {
+  glwImGui *imGUI = glwGetImGUI(win);
+  char text[100];
+  float leftSegLen = width * (cur - min) / max;
+  float thumLeft = x + leftSegLen - (GLW_SLIDER_THUMB_WIDTH / 2);
+  float thumTop = y + glwGetLineHeight(win) - (GLW_SLIDER_THUMB_HEIGHT / 2);
+  unsigned int topColor = 0;
+  unsigned int bottomColor = 0;
+  va_list args;
+  va_start(args, fmt);
+  vsnprintf(text, sizeof(text), fmt, args);
+  glwImGUIActiveIdCheck(imGUI, id, thumLeft, thumTop,
+    GLW_SLIDER_THUMB_WIDTH, GLW_SLIDER_THUMB_HEIGHT);
+  topColor = GLW_FILL_GRADIENT_COLOR_1_H;
+  bottomColor = GLW_FILL_GRADIENT_COLOR_2_H;
+  if (imGUI->activeId == id) {
+    float mouseFromLeft = (float)glwMouseX(win) - x;
+    glwSwapColor(topColor, bottomColor);
+    cur = min + (max - min) * mouseFromLeft / width;
+  }
+  if (cur < min) {
+    cur = min;
+  } else if (cur > max) {
+    cur = max;
+  }
+  glwDrawSystemText(win, x, y, text, GLW_SYSTEM_FONT_COLOR);
+  glwDrawGradientLine(x, y + glwGetLineHeight(win), leftSegLen,
+    GLW_SLIDER_HEIGHT,
+    GLW_TOOLBAR_BACKGROUND_COLOR, 0x4d4d4d);
+  glwDrawGradientLine(x + leftSegLen, y + glwGetLineHeight(win),
+    width - leftSegLen, GLW_SLIDER_HEIGHT,
+    0x4d4d4d, GLW_TOOLBAR_BACKGROUND_COLOR);
+  glwDrawRoundedRectGradientFill(thumLeft, thumTop,
+    GLW_SLIDER_THUMB_WIDTH, GLW_SLIDER_THUMB_HEIGHT,
+    GLW_SLIDER_CORNER_RADIUS,
+    topColor, bottomColor);
+  glwDrawRoundedRectBorder(thumLeft, thumTop,
+    GLW_SLIDER_THUMB_WIDTH, GLW_SLIDER_THUMB_HEIGHT,
+    GLW_SLIDER_CORNER_RADIUS, GLW_BORDER_COLOR_2);
+  return cur;
+}
diff --git a/src/glw.h b/src/glw.h
index 4d10d1ba..f094ef19 100644
--- a/src/glw.h
+++ b/src/glw.h
@@ -67,6 +67,8 @@ int glwMouseX(glwWin *win);
 int glwMouseY(glwWin *win);
 int glwImMenu(glwWin *win, int id, int x, int y, int width, int height,
   char **titles, int sel);
+float glwImSlider(glwWin *win, int id, int x, int y, int width,
+  float min, float max, float cur, char *fmt, ...);
 
 #ifdef __cplusplus
 }
diff --git a/src/glw_style.h b/src/glw_style.h
index 3877a1b7..8cce5d00 100644
--- a/src/glw_style.h
+++ b/src/glw_style.h
@@ -40,4 +40,10 @@
 
 #define GLW_MENU_BACKGROUND_COLOR 0x181818
 
+#define GLW_SLIDER_THUMB_WIDTH  20
+#define GLW_SLIDER_THUMB_HEIGHT 12
+#define GLW_SLIDER_HEIGHT       2
+
+#define GLW_SLIDER_CORNER_RADIUS 3
+
 #endif