Scrollbar: fixed minor rendering offset when borders are enabled (fix #365)

imgui.cpp

@@ -4056,9 +4056,10 @@ static void Scrollbar(ImGuiWindow* window, bool horizontal)
     bool other_scrollbar = (horizontal ? window->ScrollbarY : window->ScrollbarX);
     float other_scrollbar_size_w = other_scrollbar ? style.ScrollbarSize : 0.0f;
     const ImRect window_rect = window->Rect();
+    const float border_offset = (window->Flags & ImGuiWindowFlags_ShowBorders) ? 1.0f : 0.0f;
     ImRect bb = horizontal
-        ? ImRect(window->Pos.x, window_rect.Max.y - style.ScrollbarSize, window_rect.Max.x - other_scrollbar_size_w, window_rect.Max.y)
-        : ImRect(window_rect.Max.x - style.ScrollbarSize, window->Pos.y + window->TitleBarHeight(), window_rect.Max.x, window_rect.Max.y - other_scrollbar_size_w);
+        ? ImRect(window->Pos.x + border_offset, window_rect.Max.y - style.ScrollbarSize, window_rect.Max.x - other_scrollbar_size_w, window_rect.Max.y)
+        : ImRect(window_rect.Max.x - style.ScrollbarSize, window->Pos.y + window->TitleBarHeight() + border_offset, window_rect.Max.x, window_rect.Max.y - other_scrollbar_size_w);
 
     float window_rounding = (window->Flags & ImGuiWindowFlags_ChildWindow) ? style.ChildWindowRounding : style.WindowRounding;
     int window_rounding_corners;