Fixed _ChildWindows from leaking docking hierarchy. Added ImGuiFocusedFlags_DockHierarchy and ImGuiHoveredFlags_DockHierarchy.

docs/CHANGELOG.txt

@@ -108,6 +108,10 @@ Breaking Changes:
 - Removed GetWindowContentRegionWidth() function. keep inline redirection helper.
   Can use 'GetWindowContentRegionMax().x - GetWindowContentRegionMin().x' instead but it's not
   very useful in practice, and the only use of it in the demo was illfit.
+- (Docking branch) IsWindowFocused() and IsWindowHovered() with only the _ChildWindows flag
+  and without the _RootWindow flag used to leak docking hierarchy, so a docked window would
+  return as the child of the window hosting the dockspace. This was inconsistent and incorrect
+  with other behaviors so we fixed it. Added a new _DockHierarchy flag to opt-in this behavior.
 
 Other Changes:
 
@@ -137,6 +141,10 @@ Other Changes:
 
 Docking+Viewports Branch:
 
+- IsWindowFocused: Fixed using ImGuiFocusedFlags_ChildWindows (without _RootWindow) from leaking the
+  docking hierarchy. Added ImGuiFocusedFlags_DockHierarchy flag to consider docking hierarchy in the test.
+- IsWindowHovered: Fixed using ImGuiHoveredFlags_ChildWindows (without _RootWindow) from leaking the
+  docking hierarchy. Added ImGuiHoveredFlags_DockHierarchy flag to consider docking hierarchy in the test.
 - Docking: fixed settings load issue when mouse wheeling. (#4310)
 - Drag and Drop: Fixed using BeginDragDropSource() or BeginDragDropTarget() inside a Begin() that
   returned false because the window is docked. (#4515)

imgui.cpp

@@ -4024,7 +4024,7 @@ void ImGui::UpdateHoveredWindowAndCaptureFlags()
 
     // Modal windows prevents mouse from hovering behind them.
     ImGuiWindow* modal_window = GetTopMostPopupModal();
-    if (modal_window && g.HoveredWindow && !IsWindowChildOf(g.HoveredWindow->RootWindowDockTree, modal_window))
+    if (modal_window && g.HoveredWindow && !IsWindowChildOf(g.HoveredWindow->RootWindowDockTree, modal_window, true))
         clear_hovered_windows = true;
 
     // Disabled mouse?
@@ -7254,15 +7254,16 @@ void ImGui::PopTextWrapPos()
     window->DC.TextWrapPosStack.pop_back();
 }
 
-// FIXME: We are exposing the docking hierarchy to end-user here (via IsWindowHovered, IsWindowFocused) which is unusual.
-bool ImGui::IsWindowChildOf(ImGuiWindow* window, ImGuiWindow* potential_parent)
+bool ImGui::IsWindowChildOf(ImGuiWindow* window, ImGuiWindow* potential_parent, bool dock_hierarchy)
 {
-    if (window->RootWindowDockTree == potential_parent)
+    if ((dock_hierarchy ? window->RootWindowDockTree : window->RootWindow) == potential_parent)
         return true;
     while (window != NULL)
     {
         if (window == potential_parent)
             return true;
+        if (window == (dock_hierarchy ? window->RootWindowDockTree : window->RootWindow))
+            return false;
         window = window->ParentWindow;
     }
     return false;
@@ -7294,13 +7295,14 @@ bool ImGui::IsWindowHovered(ImGuiHoveredFlags flags)
     if ((flags & ImGuiHoveredFlags_AnyWindow) == 0)
     {
         IM_ASSERT(cur_window); // Not inside a Begin()/End()
+        const bool dock_hierarchy = (flags & ImGuiHoveredFlags_DockHierarchy) != 0;
 
         if (flags & ImGuiHoveredFlags_RootWindow)
-            cur_window = cur_window->RootWindow;
+            cur_window = dock_hierarchy ? cur_window->RootWindowDockTree : cur_window->RootWindow;
 
         bool result;
         if (flags & ImGuiHoveredFlags_ChildWindows)
-            result = IsWindowChildOf(ref_window, cur_window);
+            result = IsWindowChildOf(ref_window, cur_window, dock_hierarchy);
         else
             result = (ref_window == cur_window);
         if (!result)
@@ -7325,13 +7327,15 @@ bool ImGui::IsWindowFocused(ImGuiFocusedFlags flags)
         return false;
     if (flags & ImGuiFocusedFlags_AnyWindow)
         return true;
+
     IM_ASSERT(cur_window); // Not inside a Begin()/End()
+    const bool dock_hierarchy = (flags & ImGuiHoveredFlags_DockHierarchy) != 0;
 
     if (flags & ImGuiHoveredFlags_RootWindow)
-        cur_window = cur_window->RootWindow;
+        cur_window = dock_hierarchy ? cur_window->RootWindowDockTree : cur_window->RootWindow;
 
     if (flags & ImGuiHoveredFlags_ChildWindows)
-        return IsWindowChildOf(ref_window, cur_window);
+        return IsWindowChildOf(ref_window, cur_window, dock_hierarchy);
     else
         return (ref_window == cur_window);
 }

imgui.h

@@ -1312,7 +1312,7 @@ enum ImGuiFocusedFlags_
     ImGuiFocusedFlags_ChildWindows                  = 1 << 0,   // Return true if any children of the window is focused
     ImGuiFocusedFlags_RootWindow                    = 1 << 1,   // Test from root window (top most parent of the current hierarchy)
     ImGuiFocusedFlags_AnyWindow                     = 1 << 2,   // Return true if any window is focused. Important: If you are trying to tell how to dispatch your low-level inputs, do NOT use this. Use 'io.WantCaptureMouse' instead! Please read the FAQ!
-    //ImGuiFocusedFlags_DockHierarchy               = 1 << 3,   // Consider docking hierarchy (treat dockspace host as parent of docked window)
+    ImGuiFocusedFlags_DockHierarchy                 = 1 << 3,   // Consider docking hierarchy (treat dockspace host as parent of docked window)
     ImGuiFocusedFlags_RootAndChildWindows           = ImGuiFocusedFlags_RootWindow | ImGuiFocusedFlags_ChildWindows
 };
 
@@ -1325,7 +1325,7 @@ enum ImGuiHoveredFlags_
     ImGuiHoveredFlags_ChildWindows                  = 1 << 0,   // IsWindowHovered() only: Return true if any children of the window is hovered
     ImGuiHoveredFlags_RootWindow                    = 1 << 1,   // IsWindowHovered() only: Test from root window (top most parent of the current hierarchy)
     ImGuiHoveredFlags_AnyWindow                     = 1 << 2,   // IsWindowHovered() only: Return true if any window is hovered
-    //ImGuiHoveredFlags_DockHierarchy               = 1 << 3,   // IsWindowHovered() only: Consider docking hierarchy (treat dockspace host as parent of docked window)
+    ImGuiHoveredFlags_DockHierarchy                 = 1 << 3,   // IsWindowHovered() only: Consider docking hierarchy (treat dockspace host as parent of docked window)
     ImGuiHoveredFlags_AllowWhenBlockedByPopup       = 1 << 4,   // Return true even if a popup window is normally blocking access to this item/window
     //ImGuiHoveredFlags_AllowWhenBlockedByModal     = 1 << 4,   // Return true even if a modal popup window is normally blocking access to this item/window. FIXME-TODO: Unavailable yet.
     ImGuiHoveredFlags_AllowWhenBlockedByActiveItem  = 1 << 5,   // Return true even if an active item is blocking access to this item/window. Useful for Drag and Drop patterns.
@@ -1346,7 +1346,7 @@ enum ImGuiDockNodeFlags_
     ImGuiDockNodeFlags_NoDockingInCentralNode       = 1 << 2,   // Shared       // Disable docking inside the Central Node, which will be always kept empty.
     ImGuiDockNodeFlags_PassthruCentralNode          = 1 << 3,   // Shared       // Enable passthru dockspace: 1) DockSpace() will render a ImGuiCol_WindowBg background covering everything excepted the Central Node when empty. Meaning the host window should probably use SetNextWindowBgAlpha(0.0f) prior to Begin() when using this. 2) When Central Node is empty: let inputs pass-through + won't display a DockingEmptyBg background. See demo for details.
     ImGuiDockNodeFlags_NoSplit                      = 1 << 4,   // Shared/Local // Disable splitting the node into smaller nodes. Useful e.g. when embedding dockspaces into a main root one (the root one may have splitting disabled to reduce confusion). Note: when turned off, existing splits will be preserved.
-    ImGuiDockNodeFlags_NoResize                     = 1 << 5,   // Shared/Local // Disable resizing node using the splitter/separators. Useful with programatically setup dockspaces.
+    ImGuiDockNodeFlags_NoResize                     = 1 << 5,   // Shared/Local // Disable resizing node using the splitter/separators. Useful with programmatically setup dockspaces.
     ImGuiDockNodeFlags_AutoHideTabBar               = 1 << 6    // Shared/Local // Tab bar will automatically hide when there is a single window in the dock node.
 };
 

imgui_demo.cpp

@@ -2334,11 +2334,15 @@ static void ShowDemoWindowWidgets()
             "IsWindowFocused() = %d\n"
             "IsWindowFocused(_ChildWindows) = %d\n"
             "IsWindowFocused(_ChildWindows|_RootWindow) = %d\n"
+            "IsWindowFocused(_ChildWindows|_RootWindow|_DockHierarchy) = %d\n"
+            "IsWindowFocused(_RootWindow|_DockHierarchy) = %d\n"
             "IsWindowFocused(_RootWindow) = %d\n"
             "IsWindowFocused(_AnyWindow) = %d\n",
             ImGui::IsWindowFocused(),
             ImGui::IsWindowFocused(ImGuiFocusedFlags_ChildWindows),
             ImGui::IsWindowFocused(ImGuiFocusedFlags_ChildWindows | ImGuiFocusedFlags_RootWindow),
+            ImGui::IsWindowFocused(ImGuiFocusedFlags_ChildWindows | ImGuiFocusedFlags_RootWindow | ImGuiFocusedFlags_DockHierarchy),
+            ImGui::IsWindowFocused(ImGuiFocusedFlags_RootWindow | ImGuiFocusedFlags_DockHierarchy),
             ImGui::IsWindowFocused(ImGuiFocusedFlags_RootWindow),
             ImGui::IsWindowFocused(ImGuiFocusedFlags_AnyWindow));
 
@@ -2350,6 +2354,8 @@ static void ShowDemoWindowWidgets()
             "IsWindowHovered(_AllowWhenBlockedByActiveItem) = %d\n"
             "IsWindowHovered(_ChildWindows) = %d\n"
             "IsWindowHovered(_ChildWindows|_RootWindow) = %d\n"
+            "IsWindowHovered(_ChildWindows|_RootWindow|_DockHierarchy) = %d\n"
+            "IsWindowHovered(_RootWindow|_DockHierarchy) = %d\n"
             "IsWindowHovered(_ChildWindows|_AllowWhenBlockedByPopup) = %d\n"
             "IsWindowHovered(_RootWindow) = %d\n"
             "IsWindowHovered(_AnyWindow) = %d\n",
@@ -2358,6 +2364,8 @@ static void ShowDemoWindowWidgets()
             ImGui::IsWindowHovered(ImGuiHoveredFlags_AllowWhenBlockedByActiveItem),
             ImGui::IsWindowHovered(ImGuiHoveredFlags_ChildWindows),
             ImGui::IsWindowHovered(ImGuiHoveredFlags_ChildWindows | ImGuiHoveredFlags_RootWindow),
+            ImGui::IsWindowHovered(ImGuiHoveredFlags_ChildWindows | ImGuiHoveredFlags_RootWindow | ImGuiHoveredFlags_DockHierarchy),
+            ImGui::IsWindowHovered(ImGuiHoveredFlags_RootWindow | ImGuiHoveredFlags_DockHierarchy),
             ImGui::IsWindowHovered(ImGuiHoveredFlags_ChildWindows | ImGuiHoveredFlags_AllowWhenBlockedByPopup),
             ImGui::IsWindowHovered(ImGuiHoveredFlags_RootWindow),
             ImGui::IsWindowHovered(ImGuiHoveredFlags_AnyWindow));

imgui_internal.h

@@ -2557,7 +2557,7 @@ namespace ImGui
     IMGUI_API ImGuiWindow*  FindWindowByName(const char* name);
     IMGUI_API void          UpdateWindowParentAndRootLinks(ImGuiWindow* window, ImGuiWindowFlags flags, ImGuiWindow* parent_window);
     IMGUI_API ImVec2        CalcWindowNextAutoFitSize(ImGuiWindow* window);
-    IMGUI_API bool          IsWindowChildOf(ImGuiWindow* window, ImGuiWindow* potential_parent);
+    IMGUI_API bool          IsWindowChildOf(ImGuiWindow* window, ImGuiWindow* potential_parent, bool dock_hierarchy);
     IMGUI_API bool          IsWindowAbove(ImGuiWindow* potential_above, ImGuiWindow* potential_below);
     IMGUI_API bool          IsWindowNavFocusable(ImGuiWindow* window);
     IMGUI_API void          SetWindowPos(ImGuiWindow* window, const ImVec2& pos, ImGuiCond cond = 0);