diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 8a137d4ee..f0d1cf057 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -37,6 +37,8 @@ Breaking Changes:
 Other Changes:
 - Columns: Fixed Separator from creating an extraneous draw command. (#125)
 - Columns: Fixed Selectable with SpanAllColumns flag from creating an extraneous draw command. (#125)
+- Separator: Revert 1.70 "Declare its thickness (1.0f) to the layout" change. It's not incorrect
+  but it breaks existing some layout patterns. Will return back to it when we expose Separator flags.
 
 
 -----------------------------------------------------------------------
diff --git a/imgui_widgets.cpp b/imgui_widgets.cpp
index 2d505f56e..2d00300e1 100644
--- a/imgui_widgets.cpp
+++ b/imgui_widgets.cpp
@@ -1207,13 +1207,15 @@ void ImGui::SeparatorEx(ImGuiSeparatorFlags flags)
     ImGuiContext& g = *GImGui;
     IM_ASSERT(ImIsPowerOfTwo(flags & (ImGuiSeparatorFlags_Horizontal | ImGuiSeparatorFlags_Vertical)));   // Check that only 1 option is selected
 
+    float thickness_draw = 1.0f;
+    float thickness_layout = 0.0f;
     if (flags & ImGuiSeparatorFlags_Vertical)
     {
         // Vertical separator, for menu bars (use current line height). Not exposed because it is misleading and it doesn't have an effect on regular layout.
         float y1 = window->DC.CursorPos.y;
         float y2 = window->DC.CursorPos.y + window->DC.CurrentLineSize.y;
-        const ImRect bb(ImVec2(window->DC.CursorPos.x, y1), ImVec2(window->DC.CursorPos.x + 1.0f, y2));
-        ItemSize(ImVec2(1.0f, 0.0f));
+        const ImRect bb(ImVec2(window->DC.CursorPos.x, y1), ImVec2(window->DC.CursorPos.x + thickness_draw, y2));
+        ItemSize(ImVec2(thickness_layout, 0.0f));
         if (!ItemAdd(bb, 0))
             return;
 
@@ -1234,8 +1236,9 @@ void ImGui::SeparatorEx(ImGuiSeparatorFlags flags)
         if (columns)
             PushColumnsBackground();
 
-        const ImRect bb(ImVec2(x1, window->DC.CursorPos.y), ImVec2(x2, window->DC.CursorPos.y + 1.0f));
-        ItemSize(ImVec2(0.0f, 1.0f)); // NB: we don't provide our width so that it doesn't get feed back into AutoFit
+        // We don't provide our width to the layout so that it doesn't get feed back into AutoFit
+        const ImRect bb(ImVec2(x1, window->DC.CursorPos.y), ImVec2(x2, window->DC.CursorPos.y + thickness_draw));
+        ItemSize(ImVec2(0.0f, thickness_layout));
         if (!ItemAdd(bb, 0))
         {
             if (columns)