Nav: Fixed menuitems/selectable on menu layer (layer 1) from storing themselves in wrong layer of LastNavIds when hovered.causing inconsistencies and bugs when hovering menu with mouse then pressing ALT to return to layer 0).

NB: this is not a new bug introduced by the previous commit (which is related to nav layers), bug has been there for a while. (#787)

imgui.cpp

@@ -2446,19 +2446,19 @@ int ImGui::GetFrameCount()
     return GImGui->FrameCount;
 }
 
-static void SetNavId(ImGuiID id)
+static void SetNavId(ImGuiID id, int nav_layer)
 {
     ImGuiContext& g = *GImGui;
     IM_ASSERT(g.NavWindow);
-    IM_ASSERT(g.NavLayer == 0 || g.NavLayer == 1);
+    IM_ASSERT(nav_layer == 0 || nav_layer == 1);
     g.NavId = id;
-    g.NavWindow->NavLastIds[g.NavLayer] = g.NavId;
+    g.NavWindow->NavLastIds[nav_layer] = g.NavId;
 }
 
-static void SetNavIdAndMoveMouse(ImGuiID id, const ImRect& rect_rel)
+static void SetNavIdAndMoveMouse(ImGuiID id, int nav_layer, const ImRect& rect_rel)
 {
     ImGuiContext& g = *GImGui;
-    SetNavId(id);
+    SetNavId(id, nav_layer);
     g.NavRefRectRel = rect_rel;
     g.NavMousePosDirty = true;
     g.NavDisableHighlight = false;
@@ -2472,7 +2472,7 @@ static void NavInitWindow(ImGuiWindow* window, bool force_reinit)
     IM_ASSERT(window == g.NavWindow);
     if (!(window->Flags & ImGuiWindowFlags_ChildWindow) || (window->Flags & ImGuiWindowFlags_Popup) || (window->NavLastIds[0] == 0) || force_reinit)
     {
-        SetNavId(0);
+        SetNavId(0, g.NavLayer);
         g.NavInitDefaultRequest = true;
         g.NavInitDefaultResultId = 0;
         g.NavInitDefaultResultExplicit = false;
@@ -2579,7 +2579,7 @@ static void NavUpdate()
     {
         // Apply result from previous navigation init request (typically select the first item, unless SetItemDefaultFocus() has been called)
         IM_ASSERT(g.NavWindow);
-        SetNavId(g.NavInitDefaultResultId);
+        SetNavId(g.NavInitDefaultResultId, g.NavLayer);
         g.NavRefRectRel = g.NavInitDefaultResultRectRel;
         if (g.NavDisableMouseHover)
             g.NavMousePosDirty = true;
@@ -2627,7 +2627,7 @@ static void NavUpdate()
 
         // Apply result from previous frame navigation directional move request
         ImGui::ClearActiveID();
-        SetNavIdAndMoveMouse(g.NavMoveResultId, g.NavMoveResultRectRel);
+        SetNavIdAndMoveMouse(g.NavMoveResultId, g.NavLayer, g.NavMoveResultRectRel);
         g.NavMoveFromClampedRefRect = false;
     }
 
@@ -2712,7 +2712,7 @@ static void NavUpdate()
                 g.NavDisableHighlight = false;
                 g.NavDisableMouseHover = true;
                 if (g.NavLayer == 0 && g.NavWindow->NavLastIds[0] != 0)
-                    SetNavIdAndMoveMouse(g.NavWindow->NavLastIds[0], ImRect());
+                    SetNavIdAndMoveMouse(g.NavWindow->NavLastIds[0], g.NavLayer, ImRect());
                 else
                     NavInitWindow(g.NavWindow, true);
             }
@@ -2739,7 +2739,7 @@ static void NavUpdate()
             ImGuiWindow* parent_window = g.NavWindow->ParentWindow;
             ImGui::FocusWindow(parent_window);
             IM_ASSERT(child_window->ChildId != 0);
-            SetNavId(child_window->ChildId);
+            SetNavId(child_window->ChildId, g.NavLayer); // FIXME-NAV: Layer not necessarily correct
             g.NavIdIsAlive = false;
             if (g.NavDisableMouseHover)
                 g.NavMousePosDirty = true;
@@ -2754,7 +2754,7 @@ static void NavUpdate()
             // Leave the "menu" layer
             g.NavLayer = 0;
             if (g.NavWindow->NavLastIds[0])
-                SetNavIdAndMoveMouse(g.NavWindow->NavLastIds[0], ImRect());
+                SetNavIdAndMoveMouse(g.NavWindow->NavLastIds[0], g.NavLayer, ImRect());
             else
                 NavInitWindow(g.NavWindow, true);
         }
@@ -9737,7 +9737,7 @@ bool ImGui::Selectable(const char* label, bool selected, ImGuiSelectableFlags fl
     if (hovered && !g.NavDisableMouseHover && g.NavWindow == window && (g.IO.MouseDelta.x != 0.0f || g.IO.MouseDelta.y != 0.0f))
     {
         g.NavDisableHighlight = true;
-        SetNavId(id);
+        SetNavId(id, window->DC.NavLayerCurrent);
     }
 
     // Render