Merge branch 'master' into docking

# Conflicts:
#	backends/imgui_impl_win32.cpp

imgui.cpp

@@ -4855,6 +4855,13 @@ ImGuiIO& ImGui::GetIO()
     return GImGui->IO;
 }
 
+// This variant exists to facilitate backends experimenting with multi-threaded parallel context. (#8069, #6293, #5856)
+ImGuiIO& ImGui::GetIOEx(ImGuiContext* ctx)
+{
+    IM_ASSERT(ctx != NULL);
+    return ctx->IO;
+}
+
 ImGuiPlatformIO& ImGui::GetPlatformIO()
 {
     IM_ASSERT(GImGui != NULL && "No current context. Did you call ImGui::CreateContext() and ImGui::SetCurrentContext()?");