Merge branch 'master' into docking

ac64b65 on master seemed incorrect.

# Conflicts:
#	docs/CHANGELOG.txt
#	imgui.cpp
#	imgui_internal.h
#	imgui_widgets.cpp

backends/imgui_impl_sdl2.cpp

@@ -546,6 +546,11 @@ bool ImGui_ImplSDL2_InitForSDLRenderer(SDL_Window* window, SDL_Renderer* rendere
     return ImGui_ImplSDL2_Init(window, renderer, nullptr);
 }
 
+bool ImGui_ImplSDL2_InitForOther(SDL_Window* window)
+{
+    return ImGui_ImplSDL2_Init(window, nullptr);
+}
+
 void ImGui_ImplSDL2_Shutdown()
 {
     ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();