diff --git a/common/widgets/two_column_tree_list.cpp b/common/widgets/two_column_tree_list.cpp
index 77f74bc376..f29ff7085e 100644
--- a/common/widgets/two_column_tree_list.cpp
+++ b/common/widgets/two_column_tree_list.cpp
@@ -89,7 +89,7 @@ void TWO_COLUMN_TREE_LIST::OnSize( wxSizeEvent& aEvent )
         if( width > clamped_column_width )
             clamped_column_width = width;
 
-        width = WidthFor( GetItemText( item, m_rubber_band_column ) );
+        width = MemoWidthFor( GetItemText( item, m_rubber_band_column ) );
         if( width > rubber_max_width )
             rubber_max_width = width;
     }
@@ -119,3 +119,24 @@ void TWO_COLUMN_TREE_LIST::OnSize( wxSizeEvent& aEvent )
     }
 }
 
+
+int TWO_COLUMN_TREE_LIST::MemoWidthFor( const wxString& aStr )
+{
+    int width;
+    auto found = m_width_cache.find( aStr );
+
+    if( found == m_width_cache.end() )
+    {
+        width = WidthFor( aStr );
+        m_width_cache[aStr] = width;
+    }
+    else
+    {
+        width = found->second;
+    }
+
+    return width;
+}
+
+
+std::map<wxString, int> TWO_COLUMN_TREE_LIST::m_width_cache;
diff --git a/eeschema/component_tree_search_container.cpp b/eeschema/component_tree_search_container.cpp
index 1619bc28b0..1318eb12c3 100644
--- a/eeschema/component_tree_search_container.cpp
+++ b/eeschema/component_tree_search_container.cpp
@@ -142,7 +142,7 @@ void COMPONENT_TREE_SEARCH_CONTAINER::SetTree( TWO_COLUMN_TREE_LIST* aTree )
 
     if( m_tree )
     {
-        m_tree->AppendColumn( _( "Part" ), wxCOL_WIDTH_AUTOSIZE, wxALIGN_LEFT, wxCOL_RESIZABLE );
+        m_tree->AppendColumn( _( "Part" ), 100, wxALIGN_LEFT, wxCOL_RESIZABLE );
         m_tree->AppendColumn( _( "Description" ), 100, wxALIGN_LEFT, wxCOL_RESIZABLE );
         m_tree->SetRubberBandColumn( 1 );
     }
diff --git a/include/widgets/two_column_tree_list.h b/include/widgets/two_column_tree_list.h
index f04a42de0d..0309c7d27d 100644
--- a/include/widgets/two_column_tree_list.h
+++ b/include/widgets/two_column_tree_list.h
@@ -27,6 +27,7 @@
  */
 
 #include <wx/treelist.h>
+#include <map>
 
 #ifndef __two_column_tree_list__
 #define __two_column_tree_list__
@@ -79,8 +80,17 @@ class TWO_COLUMN_TREE_LIST : public wxTreeListCtrl
         void OnSize( wxSizeEvent& aEvent );
 
     protected:
+
+        /**
+         * Memoized version of wx WidthFor(), which returns the width in pixels
+         * required to display a string. This function is REALLY SLOW on macOS.
+         */
+        int MemoWidthFor( const wxString& aStr );
+
         int m_rubber_band_column;
         int m_clamped_min_width;
+
+        static std::map<wxString, int> m_width_cache;
 };
 
 #endif // __two_column_tree_list__