diff --git a/src/slic3r/GUI/ImGuiDoubleSlider.cpp b/src/slic3r/GUI/ImGuiDoubleSlider.cpp
index 39cbc78844..37ffcca378 100644
--- a/src/slic3r/GUI/ImGuiDoubleSlider.cpp
+++ b/src/slic3r/GUI/ImGuiDoubleSlider.cpp
@@ -360,11 +360,12 @@ void ImGuiControl::draw_thumb(const ImVec2& center, bool mark/* = false*/)
     const float line_width  = 1.5f * m_draw_opts.scale;
     const float radius      = m_draw_opts.thumb_radius();
     const float line_offset = 0.5f * radius;
+    const float rounding    = 1.5f * m_draw_opts.rounding();
 
     const float hexagon_angle = is_horizontal() ? 0.f : IM_PI * 0.5f;
 
-    ImGuiPureWrap::draw_hexagon(center, radius,              border_clr, hexagon_angle);
-    ImGuiPureWrap::draw_hexagon(center, radius - line_width, thumb_bg_clr,        hexagon_angle);
+    ImGuiPureWrap::draw_hexagon(center, radius,              border_clr,    hexagon_angle, rounding);
+    ImGuiPureWrap::draw_hexagon(center, radius - line_width, thumb_bg_clr,  hexagon_angle, rounding);
 
     if (mark) {
         ImGuiWindow* window = ImGui::GetCurrentWindow();
diff --git a/src/slic3r/GUI/ImGuiPureWrap.cpp b/src/slic3r/GUI/ImGuiPureWrap.cpp
index 4b3111acd8..41ce243b1f 100644
--- a/src/slic3r/GUI/ImGuiPureWrap.cpp
+++ b/src/slic3r/GUI/ImGuiPureWrap.cpp
@@ -296,7 +296,7 @@ bool combo(const std::string& label, const std::vector<std::string>& options, in
     return res;
 }
 
-void draw_hexagon(const ImVec2& center, float radius, ImU32 col, float start_angle)
+void draw_hexagon(const ImVec2& center, float radius, ImU32 col, float start_angle, float rounding)
 {
     if ((col & IM_COL32_A_MASK) == 0)
         return;
@@ -306,7 +306,21 @@ void draw_hexagon(const ImVec2& center, float radius, ImU32 col, float start_ang
     float a_min = start_angle;
     float a_max = start_angle + 2.f * IM_PI;
 
-    window->DrawList->PathArcTo(center, radius, a_min, a_max, 6);
+    if (rounding <= 0) {
+        window->DrawList->PathArcTo(center, radius, a_min, a_max, 6);
+    }
+    else {
+        const float a_delta = IM_PI / 4.f;
+        radius -= rounding;
+
+        for (int i = 0; i <= 6; i++) {
+            float a = a_min + ((float)i / (float)6) * (a_max - a_min);
+            if (a >= 2.f * IM_PI)
+                a -= 2.f * IM_PI;
+            ImVec2 pos = ImVec2(center.x + ImCos(a) * radius, center.y + ImSin(a) * radius);
+            window->DrawList->PathArcTo(pos, rounding, a - a_delta, a + a_delta, 5);
+        }
+    }
     window->DrawList->PathFillConvex(col);
 }
 
diff --git a/src/slic3r/GUI/ImGuiPureWrap.hpp b/src/slic3r/GUI/ImGuiPureWrap.hpp
index ab4eccab1b..ef1f04c8a5 100644
--- a/src/slic3r/GUI/ImGuiPureWrap.hpp
+++ b/src/slic3r/GUI/ImGuiPureWrap.hpp
@@ -53,7 +53,7 @@ namespace ImGuiPureWrap
     // Use selection = -1 to not mark any option as selected
     bool combo(const std::string& label, const std::vector<std::string>& options, int& selection, ImGuiComboFlags flags = 0, float label_width = 0.0f, float item_width = 0.0f);
 
-    void draw_hexagon(const ImVec2& center, float radius, ImU32 col, float start_angle = 0.f);
+    void draw_hexagon(const ImVec2& center, float radius, ImU32 col, float start_angle = 0.f, float rounding = 0.f);
 
     void text(const char* label);
     void text(const std::string& label);