Added ImGuiWindowFlags_NoFocusOnAppearing flag (#314)

imgui.cpp

@@ -3532,8 +3532,9 @@ bool ImGui::Begin(const char* name, bool* p_opened, const ImVec2& size_on_first_
         {
             window->AutoPosLastDirection = -1;
 
-            if (!(flags & (ImGuiWindowFlags_ChildWindow|ImGuiWindowFlags_Tooltip)) || (flags & ImGuiWindowFlags_Popup))
+            if (!(flags & ImGuiWindowFlags_NoFocusOnAppearing))
-                FocusWindow(window);
+                if (!(flags & (ImGuiWindowFlags_ChildWindow|ImGuiWindowFlags_Tooltip)) || (flags & ImGuiWindowFlags_Popup))
+                    FocusWindow(window);
 
             // Popup first latch mouse position, will position itself when it appears next frame
             if ((flags & ImGuiWindowFlags_Popup) != 0 && !window_pos_set_by_api)

imgui.h

@@ -456,6 +456,7 @@ enum ImGuiWindowFlags_
     ImGuiWindowFlags_NoInputs               = 1 << 9,   // Disable catching mouse or keyboard inputs
     ImGuiWindowFlags_MenuBar                = 1 << 10,  // Has a menu-bar
     ImGuiWindowFlags_HorizontalScrollbar    = 1 << 11,  // Enable horizontal scrollbar (off by default). You need to use SetNextWindowContentSize(ImVec2(width,0.0f)); prior to calling Begin() to specify width. Read code in imgui_demo in the "Horizontal Scrolling" section.
+    ImGuiWindowFlags_NoFocusOnAppearing     = 1 << 12,  // Disable taking focus when transitioning from hidden to visible state
     // [Internal]
     ImGuiWindowFlags_ChildWindow            = 1 << 20,  // Don't use! For internal use by BeginChild()
     ImGuiWindowFlags_ChildWindowAutoFitX    = 1 << 21,  // Don't use! For internal use by BeginChild()