start with initial size

example/color_node_editor.cpp

@@ -130,6 +130,7 @@ class ColorNodeEditor
 
     void show()
     {
+        static bool first_show = true;
         // Update timer context
         current_time_seconds = 0.001f * SDL_GetTicks();
 
@@ -640,14 +641,24 @@ class ColorNodeEditor
             }
         }
 
+        if (first_show)
+        {
+            ImGui::Dummy(ImVec2(500, 500));
+        }
         ImGui::End();
 
         // The color output window
 
         const ImU32 color =
             root_node_id_ != -1 ? evaluate(graph_, root_node_id_) : IM_COL32(255, 20, 147, 255);
         ImGui::PushStyleColor(ImGuiCol_WindowBg, color);
+        ImGui::SetNextWindowPos(ImVec2(600, 60), ImGuiCond_FirstUseEver);
         ImGui::Begin("output color");
+        if (first_show)
+        {
+            ImGui::Dummy(ImVec2(150, 150));
+            first_show = false;
+        }
         ImGui::End();
         ImGui::PopStyleColor();
     }

example/hello.cpp

@@ -31,7 +31,12 @@ class HelloWorldNodeEditor
 
         ImNodes::EndNode();
         ImNodes::EndNodeEditor();
-
+        static bool first_show = true;
+        if (first_show)
+        {
+            ImGui::Dummy(ImVec2(500, 500));
+            first_show = false;
+        }
         ImGui::End();
     }
 };

example/multi_editor.cpp

@@ -30,6 +30,7 @@ struct Editor
     std::vector<Node>     nodes;
     std::vector<Link>     links;
     int                   current_id = 0;
+    bool first_show = true;
 };
 
 void show_editor(const char* editor_name, Editor& editor)
@@ -106,6 +107,11 @@ void show_editor(const char* editor_name, Editor& editor)
         }
     }
 
+    if (editor.first_show)
+    {
+        ImGui::Dummy(ImVec2(300, 300));
+        editor.first_show = false;
+    }
     ImGui::End();
 }
 
@@ -130,6 +136,7 @@ void NodeEditorInitialize()
 void NodeEditorShow()
 {
     show_editor("editor1", editor1);
+    ImGui::SetNextWindowPos(ImVec2(400, 60), ImGuiCond_FirstUseEver);
     show_editor("editor2", editor2);
 }
 

example/save_load.cpp

@@ -110,6 +110,12 @@ class SaveLoadEditor
             }
         }
 
+        static bool first_show = true;
+        if (first_show)
+        {
+            ImGui::Dummy(ImVec2(600, 500));
+            first_show = false;
+        }
         ImGui::End();
     }