diff --git a/imgui.cpp b/imgui.cpp
index 2254b9b08..f2be79bc4 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -204,6 +204,7 @@
  Here is a change-log of API breaking changes, if you are using one of the functions listed, expect to have to fix some code.
  Also read releases logs https://github.com/ocornut/imgui/releases for more details.
 
+ - 2017/10/17 (1.52) - marked the old 5-parameters version of Begin() as obsolete (still available). Use SetNextWindowSize()+Begin() instead!
  - 2017/10/11 (1.52) - renamed AlignFirstTextHeightToWidgets() to AlignTextToFramePadding(). Kept inline redirection function (will obsolete).
  - 2017/09/25 (1.52) - removed SetNextWindowPosCenter() because SetNextWindowPos() now has the optional pivot information to do the same and more. Kept redirection function (will obsolete). 
  - 2017/08/25 (1.52) - io.MousePos needs to be set to ImVec2(-FLT_MAX,-FLT_MAX) when mouse is unavailable/missing. Previously ImVec2(-1,-1) was enough but we now accept negative mouse coordinates. In your binding if you need to support unavailable mouse, make sure to replace "io.MousePos = ImVec2(-1,-1)" with "io.MousePos = ImVec2(-FLT_MAX,-FLT_MAX)".
@@ -4022,31 +4023,6 @@ static ImGuiCol GetWindowBgColorIdxFromFlags(ImGuiWindowFlags flags)
     return ImGuiCol_WindowBg;
 }
 
-// FIXME-OBSOLETE: Old Begin() API, avoid calling this version directly!
-bool ImGui::Begin(const char* name, bool* p_open, const ImVec2& size_on_first_use, float bg_alpha_override, ImGuiWindowFlags flags)
-{
-    ImGuiContext& g = *GImGui;
-
-    // Old API feature: we could pass the initial window size as a parameter, however this was very misleading because in most cases it would only affect the window when it didn't have storage in the .ini file.
-    if (size_on_first_use.x != 0.0f || size_on_first_use.y != 0.0f)
-        SetNextWindowSize(size_on_first_use, ImGuiCond_FirstUseEver);
-
-    // Old API feature: we could override the window background alpha with a parameter. This is actually tricky to reproduce manually because: 
-    // (1) there are multiple variants of WindowBg (popup, tooltip, etc.) and (2) you can't call PushStyleColor before Begin and PopStyleColor just after Begin() because of how CheckStackSizes() behave.
-    // The user-side solution is to do backup = GetStyleColorVec4(ImGuiCol_xxxBG), PushStyleColor(ImGuiCol_xxxBg), Begin, PushStyleColor(ImGuiCol_xxxBg, backup), [...], PopStyleColor(), End(); PopStyleColor() - which is super awkward.
-    // The alpha override was rarely used but for now we'll leave the Begin() variant around for a bit. We may either lift the constraint on CheckStackSizes() either add a SetNextWindowBgAlpha() helper that does it magically.
-    const ImGuiCol bg_color_idx = GetWindowBgColorIdxFromFlags(flags);
-    const ImVec4 bg_color_backup = g.Style.Colors[bg_color_idx];
-    if (bg_alpha_override >= 0.0f)
-        g.Style.Colors[bg_color_idx].w = bg_alpha_override;
-
-    bool ret = Begin(name, p_open, flags);
-
-    if (bg_alpha_override >= 0.0f)
-        g.Style.Colors[bg_color_idx] = bg_color_backup;
-    return ret;
-}
-
 // Push a new ImGui window to add widgets to.
 // - A default window called "Debug" is automatically stacked at the beginning of every frame so you can use widgets without explicitly calling a Begin/End pair.
 // - Begin/End can be called multiple times during the frame with the same window name to append content.
@@ -4589,6 +4565,32 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
     return !window->SkipItems;
 }
 
+// Old Begin() API with 5 parameters, avoid calling this version directly! Use SetNextWindowSize()+Begin() instead.
+#ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+bool ImGui::Begin(const char* name, bool* p_open, const ImVec2& size_on_first_use, float bg_alpha_override, ImGuiWindowFlags flags)
+{
+    // Old API feature: we could pass the initial window size as a parameter, however this was very misleading because in most cases it would only affect the window when it didn't have storage in the .ini file.
+    if (size_on_first_use.x != 0.0f || size_on_first_use.y != 0.0f)
+        SetNextWindowSize(size_on_first_use, ImGuiCond_FirstUseEver);
+
+    // Old API feature: we could override the window background alpha with a parameter. This is actually tricky to reproduce manually because: 
+    // (1) there are multiple variants of WindowBg (popup, tooltip, etc.) and (2) you can't call PushStyleColor before Begin and PopStyleColor just after Begin() because of how CheckStackSizes() behave.
+    // The user-side solution is to do backup = GetStyleColorVec4(ImGuiCol_xxxBG), PushStyleColor(ImGuiCol_xxxBg), Begin, PushStyleColor(ImGuiCol_xxxBg, backup), [...], PopStyleColor(), End(); PopStyleColor() - which is super awkward.
+    // The alpha override was rarely used but for now we'll leave the Begin() variant around for a bit. We may either lift the constraint on CheckStackSizes() either add a SetNextWindowBgAlpha() helper that does it magically.
+    ImGuiContext& g = *GImGui;
+    const ImGuiCol bg_color_idx = GetWindowBgColorIdxFromFlags(flags);
+    const ImVec4 bg_color_backup = g.Style.Colors[bg_color_idx];
+    if (bg_alpha_override >= 0.0f)
+        g.Style.Colors[bg_color_idx].w = bg_alpha_override;
+
+    bool ret = Begin(name, p_open, flags);
+
+    if (bg_alpha_override >= 0.0f)
+        g.Style.Colors[bg_color_idx] = bg_color_backup;
+    return ret;
+}
+#endif // IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+
 void ImGui::End()
 {
     ImGuiContext& g = *GImGui;
diff --git a/imgui.h b/imgui.h
index 8984f9910..17c39f5ea 100644
--- a/imgui.h
+++ b/imgui.h
@@ -132,7 +132,6 @@ namespace ImGui
 
     // Window
     IMGUI_API bool          Begin(const char* name, bool* p_open = NULL, ImGuiWindowFlags flags = 0);                                                   // push window to the stack and start appending to it. see .cpp for details. return false when window is collapsed, so you can early out in your code. 'bool* p_open' creates a widget on the upper-right to close the window (which sets your bool to false).
-    IMGUI_API bool          Begin(const char* name, bool* p_open, const ImVec2& size_on_first_use, float bg_alpha = -1.0f, ImGuiWindowFlags flags = 0); // OBSOLETE. this is the older/longer API. the extra parameters aren't very relevant. call SetNextWindowSize() instead if you want to set a window size. For regular windows, 'size_on_first_use' only applies to the first time EVER the window is created and probably not what you want! might obsolete this API eventually.
     IMGUI_API void          End();                                                                                                                      // finish appending to current window, pop it off the window stack.
     IMGUI_API bool          BeginChild(const char* str_id, const ImVec2& size = ImVec2(0,0), bool border = false, ImGuiWindowFlags extra_flags = 0);    // begin a scrolling region. size==0.0f: use remaining window size, size<0.0f: use remaining window size minus abs(size). size>0.0f: fixed size. each axis can use a different mode, e.g. ImVec2(0,400).
     IMGUI_API bool          BeginChild(ImGuiID id, const ImVec2& size = ImVec2(0,0), bool border = false, ImGuiWindowFlags extra_flags = 0);            // "
@@ -488,6 +487,7 @@ namespace ImGui
 
     // Obsolete functions (Will be removed! Also see 'API BREAKING CHANGES' section in imgui.cpp)
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+    bool                    Begin(const char* name, bool* p_open, const ImVec2& size_on_first_use, float bg_alpha_override = -1.0f, ImGuiWindowFlags flags = 0); // OBSOLETE 1.52+. use SetNextWindowSize() instead if you want to set a window size.
     static inline void      AlignFirstTextHeightToWidgets() { AlignTextToFramePadding(); }     // OBSOLETE 1.52+
     void                    SetNextWindowPosCenter(ImGuiCond cond = 0);                        // OBSOLETE 1.52+
     static inline bool      IsItemHoveredRect() { return IsItemRectHovered(); }                // OBSOLETE 1.51+