gui: use tab to merge editor and source windows

app/gui/application.cpp

@@ -105,7 +105,7 @@ application::show()
     editor* ed = nullptr;
     while (editors.next(ed)) {
         if (ed->show) {
-            if (!ed->show_editor()) {
+            if (!ed->show_window()) {
                 editor* next = ed;
                 editors.next(next);
                 free_editor(*ed);

app/gui/application.hpp

@@ -265,9 +265,6 @@ struct editor
       file_discrete_outs;
     std::vector<observation_output> observation_outputs;
 
-    void show_sources_window(bool* is_show);
-    void show_menu_sources(const char* title, source& src);
-
     template<typename Function, typename... Args>
     constexpr void observation_dispatch(const u32 index,
                                         Function&& f,
@@ -328,7 +325,6 @@ struct editor
     bool show_save_file_dialog = false;
     bool show_select_directory_dialog = false;
     bool show_settings = false;
-    bool show_sources = false;
 
     struct settings_manager
     {
@@ -432,8 +428,11 @@ struct editor
     void show_model_dynamics(model& mdl) noexcept;
     void show_model_cluster(cluster& mdl) noexcept;
     void show_top() noexcept;
+    void show_sources() noexcept;
+    void show_editor() noexcept;
+    void show_menu_sources(const char* title, source& src);
 
-    bool show_editor() noexcept;
+    bool show_window() noexcept;
 };
 
 struct window_logger

app/gui/sources.cpp

@@ -267,16 +267,8 @@ show_random_distribution_input(random_source& src) noexcept
 }
 
 void
-editor::show_sources_window(bool* is_show)
+editor::show_sources() noexcept
 {
-    ImGui::SetNextWindowPos(ImVec2(70, 450), ImGuiCond_FirstUseEver);
-    ImGui::SetNextWindowSize(ImVec2(400, 300), ImGuiCond_FirstUseEver);
-
-    if (!ImGui::Begin("External sources", is_show)) {
-        ImGui::End();
-        return;
-    }
-
     static bool show_file_dialog = false;
     static irt::constant_source* constant_ptr = nullptr;
     static irt::binary_file_source* binary_file_ptr = nullptr;
@@ -626,8 +618,6 @@ editor::show_sources_window(bool* is_show)
             }
         }
     }
-
-    ImGui::End();
 }
 
 void