TabBar: Fixed unfocused tab bar separator color (was using ImGuiCol_Tab, should use ImGuiCol_TabUnfocusedActive).

docs/CHANGELOG.txt

@@ -51,6 +51,7 @@ Other Changes:
   any more. Forwarding can still be disabled by setting ImGuiWindowFlags_NoInputs. (amend #1502, #1380).
 - Scrollbar: Avoid overlapping the opposite side when window (often a child window) is forcibly too small.
 - Combo: Hide arrow when there's not enough space even for the square button.
+- TabBar: Fixed unfocused tab bar separator color (was using ImGuiCol_Tab, should use ImGuiCol_TabUnfocusedActive).
 - Word-wrapping: Fixed overzealous word-wrapping when glyph edge lands exactly on the limit. Because
   of this, auto-fitting exactly unwrapped text would make it wrap. (fixes initial 1.15 commit, 78645a7d).
 - Scrolling: Added SetScrollHereX(), SetScrollFromPosX() for completeness. (#1580) [@kevreco]

imgui_widgets.cpp

@@ -6347,7 +6347,7 @@ bool    ImGui::BeginTabBarEx(ImGuiTabBar* tab_bar, const ImRect& tab_bar_bb, ImG
     window->DC.CursorPos.x = tab_bar->BarRect.Min.x;
 
     // Draw separator
-    const ImU32 col = GetColorU32((flags & ImGuiTabBarFlags_IsFocused) ? ImGuiCol_TabActive : ImGuiCol_Tab);
+    const ImU32 col = GetColorU32((flags & ImGuiTabBarFlags_IsFocused) ? ImGuiCol_TabActive : ImGuiCol_TabUnfocusedActive);
     const float y = tab_bar->BarRect.Max.y - 1.0f;
     {
         const float separator_min_x = tab_bar->BarRect.Min.x - ImFloor(window->WindowPadding.x * 0.5f);