UI: Expand linked/overriden collections by default in the Outliner

When linking or overriding an instanced collection, the new collection item in
the Outliner is now un-collapsed by default.
Linking and overriding is typically used in production scenes, where
collections tend to contain many items (children, grand-children, etc.). If all
collections in that hierarchy are expanded by default, the Outliner gets
flooded with items. So users ended up manually collapsing the collections.

Part of T76555.

Reviewed by: Andy Goralczyk, Bastien Montange.

Differential Revision: https://developer.blender.org/D7626

1 files changed, 2 insertions, 2 deletions

diff --git a/source/blender/editors/space_outliner/outliner_tree.c b/source/blender/editors/space_outliner/outliner_tree.c
index 7bb62b0d1e2..d6efe683673 100644
--- a/source/blender/editors/space_outliner/outliner_tree.c
+++ b/source/blender/editors/space_outliner/outliner_tree.c
@@ -1427,9 +1427,9 @@ static void outliner_add_layer_collections_recursive(SpaceOutliner *soops,
       ten->name = id->name + 2;
       ten->directdata = lc;
 
-      /* Open by default. */
+      /* Open by default, except linked collections, which may contain many elements. */
       TreeStoreElem *tselem = TREESTORE(ten);
-      if (!tselem->used) {
+      if (!(tselem->used || ID_IS_LINKED(id) || ID_IS_OVERRIDE_LIBRARY(id))) {
         tselem->flag &= ~TSE_CLOSED;
       }