diff --git a/implot.h b/implot.h
index 997d96f..fb1ff02 100644
--- a/implot.h
+++ b/implot.h
@@ -45,6 +45,9 @@
 // [SECTION] Obsolete API
 
 #pragma once
+#ifndef IMGUI_DEFINE_MATH_OPERATORS
+#define IMGUI_DEFINE_MATH_OPERATORS
+#endif
 #include "imgui.h"
 
 //-----------------------------------------------------------------------------
diff --git a/implot.cpp b/implot.cpp
index b76ffb7..22e4261 100644
--- a/implot.cpp
+++ b/implot.cpp
@@ -132,6 +132,11 @@ You can read releases logs https://github.com/epezent/implot/releases for more d
 #define ImDrawFlags_RoundCornersAll ImDrawCornerFlags_All
 #endif
 
+// Support for pre-1.89.7 versions.
+#if (IMGUI_VERSION_NUM < 18966)
+#define ImGuiButtonFlags_AllowOverlap ImGuiButtonFlags_AllowItemOverlap
+#endif
+
 // Visual Studio warnings
 #ifdef _MSC_VER
 #pragma warning (disable: 4996) // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
@@ -1802,7 +1807,7 @@ bool UpdateInput(ImPlotPlot& plot) {
 
     // BUTTON STATE -----------------------------------------------------------
 
-    const ImGuiButtonFlags plot_button_flags = ImGuiButtonFlags_AllowItemOverlap
+    const ImGuiButtonFlags plot_button_flags = ImGuiButtonFlags_AllowOverlap
                                              | ImGuiButtonFlags_PressedOnClick
                                              | ImGuiButtonFlags_PressedOnDoubleClick
                                              | ImGuiButtonFlags_MouseButtonLeft
@@ -1812,7 +1817,9 @@ bool UpdateInput(ImPlotPlot& plot) {
                                              | plot_button_flags;
 
     const bool plot_clicked = ImGui::ButtonBehavior(plot.PlotRect,plot.ID,&plot.Hovered,&plot.Held,plot_button_flags);
-    ImGui::SetItemAllowOverlap();
+#if (IMGUI_VERSION_NUM < 18966)
+    ImGui::SetItemAllowOverlap(); // Handled by ButtonBehavior()
+#endif
 
     if (plot_clicked) {
         if (!ImHasFlag(plot.Flags, ImPlotFlags_NoBoxSelect) && IO.MouseClicked[gp.InputMap.Select] && ImHasFlag(IO.KeyMods, gp.InputMap.SelectMod)) {
@@ -3378,7 +3385,7 @@ bool BeginSubplots(const char* title, int rows, int cols, const ImVec2& size, Im
             ImGui::KeepAliveID(sep_id);
             const ImRect sep_bb = ImRect(subplot.GridRect.Min.x, ypos-SUBPLOT_SPLITTER_HALF_THICKNESS, subplot.GridRect.Max.x, ypos+SUBPLOT_SPLITTER_HALF_THICKNESS);
             bool sep_hov = false, sep_hld = false;
-            const bool sep_clk = ImGui::ButtonBehavior(sep_bb, sep_id, &sep_hov, &sep_hld, ImGuiButtonFlags_FlattenChildren | ImGuiButtonFlags_AllowItemOverlap | ImGuiButtonFlags_PressedOnClick | ImGuiButtonFlags_PressedOnDoubleClick);
+            const bool sep_clk = ImGui::ButtonBehavior(sep_bb, sep_id, &sep_hov, &sep_hld, ImGuiButtonFlags_FlattenChildren | ImGuiButtonFlags_PressedOnClick | ImGuiButtonFlags_PressedOnDoubleClick);
             if ((sep_hov && G.HoveredIdTimer > SUBPLOT_SPLITTER_FEEDBACK_TIMER) || sep_hld) {
                 if (sep_clk && ImGui::IsMouseDoubleClicked(0)) {
                     float p = (subplot.RowRatios[r] + subplot.RowRatios[r+1])/2;
@@ -3408,7 +3415,7 @@ bool BeginSubplots(const char* title, int rows, int cols, const ImVec2& size, Im
             ImGui::KeepAliveID(sep_id);
             const ImRect sep_bb = ImRect(xpos-SUBPLOT_SPLITTER_HALF_THICKNESS, subplot.GridRect.Min.y, xpos+SUBPLOT_SPLITTER_HALF_THICKNESS, subplot.GridRect.Max.y);
             bool sep_hov = false, sep_hld = false;
-            const bool sep_clk = ImGui::ButtonBehavior(sep_bb, sep_id, &sep_hov, &sep_hld, ImGuiButtonFlags_FlattenChildren | ImGuiButtonFlags_AllowItemOverlap | ImGuiButtonFlags_PressedOnClick | ImGuiButtonFlags_PressedOnDoubleClick);
+            const bool sep_clk = ImGui::ButtonBehavior(sep_bb, sep_id, &sep_hov, &sep_hld, ImGuiButtonFlags_FlattenChildren | ImGuiButtonFlags_PressedOnClick | ImGuiButtonFlags_PressedOnDoubleClick);
             if ((sep_hov && G.HoveredIdTimer > SUBPLOT_SPLITTER_FEEDBACK_TIMER) || sep_hld) {
                 if (sep_clk && ImGui::IsMouseDoubleClicked(0)) {
                     float p = (subplot.ColRatios[c] + subplot.ColRatios[c+1])/2;