diff --git a/imgui.cpp b/imgui.cpp
index 70d39e985..24cfe986b 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -2130,8 +2130,10 @@ static ImGuiDir NavScoreItemGetQuadrant(float dx, float dy)
 
 static float NavScoreItemDistInterval(float a0, float a1, float b0, float b1)
 {
-    if (a1 < b0) return a1 - b0;
-    if (b1 < a0) return a0 - b1;
+    if (a1 < b0) 
+        return a1 - b0;
+    if (b1 < a0) 
+        return a0 - b1;
     return 0.0f;
 }
 
@@ -3133,9 +3135,11 @@ static void ImGui::NavUpdate()
     }
 
     // For scoring we use a single segment on the left side our current item bounding box (not touching the edge to avoid box overlap with zero-spaced items)
-    g.NavScoringRectScreen = g.NavWindow ? ImRect(g.NavWindow->Pos + g.NavWindow->NavRectRel[g.NavLayer].Min, g.NavWindow->Pos + g.NavWindow->NavRectRel[g.NavLayer].Max) : ImRect();
+    ImRect nav_rect_rel = (g.NavWindow && g.NavWindow->NavRectRel[g.NavLayer].IsFinite()) ? g.NavWindow->NavRectRel[g.NavLayer] : ImRect(0,0,0,0);
+    g.NavScoringRectScreen = g.NavWindow ? ImRect(g.NavWindow->Pos + nav_rect_rel.Min, g.NavWindow->Pos + nav_rect_rel.Max) : GetViewportRect();
     g.NavScoringRectScreen.Min.x = ImMin(g.NavScoringRectScreen.Min.x + 1.0f, g.NavScoringRectScreen.Max.x);
     g.NavScoringRectScreen.Max.x = g.NavScoringRectScreen.Min.x;
+    IM_ASSERT(!g.NavScoringRectScreen.IsInverted()); // Ensure if we have a finite, non-inverted bounding box here will allows us to remove extraneous fabsf() calls in NavScoreItem().
     //g.OverlayDrawList.AddRect(g.NavScoringRectScreen.Min, g.NavScoringRectScreen.Max, IM_COL32(255,200,0,255)); // [DEBUG]
 #if IMGUI_DEBUG_NAV_RECTS
     if (g.NavWindow) { for (int layer = 0; layer < 2; layer++) g.OverlayDrawList.AddRect(g.NavWindow->Pos + g.NavWindow->NavRectRel[layer].Min, g.NavWindow->Pos + g.NavWindow->NavRectRel[layer].Max, IM_COL32(255,200,0,255)); } // [DEBUG]