UI: Avoid rebuilding Outliner tree when opening/collapsing items

In big files, the Outliner would have a noticeable lag when opening or
collapsing items. That was because the entire tree was rebuilt, which isn't
actually needed in most cases. So we avoid it where possible now.

1 files changed, 2 insertions, 0 deletions

diff --git a/source/blender/editors/space_outliner/outliner_intern.h b/source/blender/editors/space_outliner/outliner_intern.h
index 3a928485711..32a67d57d0f 100644
--- a/source/blender/editors/space_outliner/outliner_intern.h
+++ b/source/blender/editors/space_outliner/outliner_intern.h
@@ -228,6 +228,8 @@ void outliner_build_tree(struct Main *mainvar,
                          struct SpaceOutliner *soops,
                          struct ARegion *region);
 
+bool outliner_element_needs_rebuild_on_open_change(const TreeStoreElem *tselem);
+
 typedef struct IDsSelectedData {
   struct ListBase selected_array;
 } IDsSelectedData;