Fix build for removal of ImGuiColorEditFlags_AlphaPreview in IMGUI_VERSION_NUM=19173

Only necessary when using IMGUI_DISABLE_OBSOLETE_FUNCTIONS.

Author: ocornut

implot.cpp

@@ -5005,9 +5005,15 @@ void ShowStyleEditor(ImPlotStyle* ref) {
             filter.Draw("Filter colors", ImGui::GetFontSize() * 16);
 
             static ImGuiColorEditFlags alpha_flags = ImGuiColorEditFlags_AlphaPreviewHalf;
+#if IMGUI_VERSION_NUM < 19173
             if (ImGui::RadioButton("Opaque", alpha_flags == ImGuiColorEditFlags_None))             { alpha_flags = ImGuiColorEditFlags_None; } ImGui::SameLine();
             if (ImGui::RadioButton("Alpha",  alpha_flags == ImGuiColorEditFlags_AlphaPreview))     { alpha_flags = ImGuiColorEditFlags_AlphaPreview; } ImGui::SameLine();
             if (ImGui::RadioButton("Both",   alpha_flags == ImGuiColorEditFlags_AlphaPreviewHalf)) { alpha_flags = ImGuiColorEditFlags_AlphaPreviewHalf; } ImGui::SameLine();
+#else
+            if (ImGui::RadioButton("Opaque", alpha_flags == ImGuiColorEditFlags_AlphaOpaque))      { alpha_flags = ImGuiColorEditFlags_AlphaOpaque; } ImGui::SameLine();
+            if (ImGui::RadioButton("Alpha",  alpha_flags == ImGuiColorEditFlags_None))             { alpha_flags = ImGuiColorEditFlags_None; } ImGui::SameLine();
+            if (ImGui::RadioButton("Both",   alpha_flags == ImGuiColorEditFlags_AlphaPreviewHalf)) { alpha_flags = ImGuiColorEditFlags_AlphaPreviewHalf; } ImGui::SameLine();
+#endif
             HelpMarker(
                 "In the color list:\n"
                 "Left-click on colored square to open color picker,\n"