Comments. Examples: added empty if (MenuItem()) {} statements in more places to better document the typical use cases (#126)

imgui.cpp

@@ -11374,8 +11374,8 @@ static void ShowExampleAppMainMenuBar()
 static void ShowExampleMenuFile()
 {
     ImGui::MenuItem("(dummy menu)", NULL, false, false);
-    ImGui::MenuItem("New");
-    ImGui::MenuItem("Open", "Ctrl+O");
+    if (ImGui::MenuItem("New")) {}
+    if (ImGui::MenuItem("Open", "Ctrl+O")) {}
     if (ImGui::BeginMenu("Open Recent"))
     {
         ImGui::MenuItem("fish_hat.c");
@@ -11394,8 +11394,8 @@ static void ShowExampleMenuFile()
         }
         ImGui::EndMenu();
     }
-    ImGui::MenuItem("Save", "Ctrl+S");
-    ImGui::MenuItem("Save As..");
+    if (ImGui::MenuItem("Save", "Ctrl+S")) {}
+    if (ImGui::MenuItem("Save As..")) {}
     ImGui::Separator();
     if (ImGui::BeginMenu("Options"))
     {
@@ -11415,7 +11415,7 @@ static void ShowExampleMenuFile()
             ImGui::MenuItem(ImGui::GetStyleColName((ImGuiCol)i));
         ImGui::EndMenu();
     }
-    ImGui::MenuItem("Quit", "Alt+F4");
+    if (ImGui::MenuItem("Quit", "Alt+F4")) {}
 }
 
 static void ShowExampleAppAutoResize(bool* opened)

imgui.h

@@ -306,8 +306,8 @@ namespace ImGui
     IMGUI_API void          EndMenuBar();
     IMGUI_API bool          BeginMenu(const char* label);                                       // create a sub-menu entry. only call EndMenu() if this returns true!
     IMGUI_API void          EndMenu();
-    IMGUI_API bool          MenuItem(const char* label, const char* shortcut = NULL, bool selected = false, bool enabled = true);  // shortcuts are displayed for convenience but not processed by ImGui
-    IMGUI_API bool          MenuItem(const char* label, const char* shortcut, bool* p_selected, bool enabled = true);
+    IMGUI_API bool          MenuItem(const char* label, const char* shortcut = NULL, bool selected = false, bool enabled = true);  // return true when activated. shortcuts are displayed for convenience but not processed by ImGui
+    IMGUI_API bool          MenuItem(const char* label, const char* shortcut, bool* p_selected, bool enabled = true);              // return true when activated + toggle (*p_selected) if p_selected != NULL
 
     // Widgets: Value() Helpers. Output single value in "name: value" format (tip: freely declare your own within the ImGui namespace!)
     IMGUI_API void          Value(const char* prefix, bool b);