Speed up removing items from SPCanvasGroup

This shortcut is possible as there are no duplicate items in
SPCanvasGroup. It reverts to the behavior before
  ab7cc89c4f9f938575e777530c31312cde116208
which introduced a severe performance regression when deselecting
paths with many nodes while the node tool is active.

Fixed bugs:
  - https://bugs.launchpad.net/inkscape/+bug/1652100
  - https://bugs.launchpad.net/inkscape/+bug/1745763

1 files changed, 5 insertions, 2 deletions

diff --git a/src/display/sp-canvas.cpp b/src/display/sp-canvas.cpp
index 20ad27bf5..c717bc7ae 100644
--- a/src/display/sp-canvas.cpp
+++ b/src/display/sp-canvas.cpp
@@ -905,9 +905,12 @@ void SPCanvasGroup::add(SPCanvasItem *item)
 
 void SPCanvasGroup::remove(SPCanvasItem *item)
 {
-
     g_return_if_fail(item != NULL);
-    items.remove(item);
+
+    auto position = std::find(items.begin(), items.end(), item);
+    if (position != items.end()) {
+        items.erase(position);
+    }
 
     // Unparent the child
     item->parent = NULL;