diff --git a/core/mui/cairo_icon_over_button.rb b/core/mui/cairo_icon_over_button.rb
index 5c42745..c86caa2 100644
--- a/core/mui/cairo_icon_over_button.rb
+++ b/core/mui/cairo_icon_over_button.rb
@@ -58,6 +58,7 @@ module Gdk::IconOverButton
   # - _gy_MiraclePainter 全体から見たy座標
   def point_moved_main_icon(gx, gy)
     icon_position = globalpos2iconpos(gx, gy)
+    @tree.pointer_on_main_icon = !!icon_position
     if icon_position
       if current_icon_pos != icon_position
         on_modify
diff --git a/core/mui/gtk_tree_view_pretty_scroll.rb b/core/mui/gtk_tree_view_pretty_scroll.rb
index 539a602..f7876f4 100644
--- a/core/mui/gtk_tree_view_pretty_scroll.rb
+++ b/core/mui/gtk_tree_view_pretty_scroll.rb
@@ -11,6 +11,7 @@ module Gtk::TreeViewPrettyScroll

   def initialize(*a)
     super
+    pointer_on_main_icon = false # メインアイコン上にポインタがあるなら真
     scroll_to_top_animation = false # 自動スクロールアニメーション中なら真
     get_scroll_to_top_animation_id = 0
     scroll_to_top_animation_id = lambda{
@@ -45,7 +46,19 @@ module Gtk::TreeViewPrettyScroll
   def scroll_to_zero_lator!
     @scroll_to_zero_lator = true end

+  def pointer_on_main_icon
+    atomic {
+      @pointer_on_main_icon
+    }
+  end
+
+  def pointer_on_main_icon=(v)
+    atomic {
+      @pointer_on_main_icon = v
+    }
+  end
+
   def scroll_to_zero?
-    defined?(@scroll_to_zero_lator) and @scroll_to_zero_lator end
+    !pointer_on_main_icon and defined?(@scroll_to_zero_lator) and @scroll_to_zero_lator end

 end