Examples: added tests for Combo box in sub-menu test and MenuItem in a normal window (#272)

imgui.cpp

@@ -11705,6 +11705,17 @@ void ImGui::ShowTestWindow(bool* opened)
                 ShowExampleMenuFile();
                 ImGui::EndPopup();
             }
+
+            ImGui::TextWrapped("Below we are testing adding menu items to a regular window. It's rather unusual but should work!");
+            ImGui::Separator();
+            ImGui::MenuItem("Menu item", "CTRL+M");
+            if (ImGui::BeginMenu("Menu"))
+            {
+                ShowExampleMenuFile();
+                ImGui::EndMenu();
+            }
+            ImGui::Separator();
+
             ImGui::TreePop();
         }
 
@@ -12172,8 +12183,10 @@ static void ShowExampleMenuFile()
             ImGui::Text("Scrolling Text %d", i);
         ImGui::EndChild();
         static float f = 0.5f;
+        static int n = 0;
         ImGui::SliderFloat("Value", &f, 0.0f, 1.0f);
         ImGui::InputFloat("Input", &f, 0.1f);
+        ImGui::Combo("Combo", &n, "Yes\0No\0Maybe\0\0");
         ImGui::EndMenu();
     }
     if (ImGui::BeginMenu("Colors"))