diff --git a/Action.c b/Action.c
index 551c426b6..b7652487f 100644
--- a/Action.c
+++ b/Action.c
@@ -242,6 +242,9 @@ static Htop_Reaction actionToggleTreeView(State* st) {
 
 static Htop_Reaction actionExpandOrCollapseAllBranches(State* st) {
    ScreenSettings* ss = st->settings->ss;
+   if (!ss->treeView) {
+      return HTOP_OK;
+   }
    ss->allBranchesCollapsed = !ss->allBranchesCollapsed;
    if (ss->allBranchesCollapsed)
       ProcessList_collapseAllBranches(st->pl);
diff --git a/ProcessList.c b/ProcessList.c
index fcc77a5fe..bbaddd862 100644
--- a/ProcessList.c
+++ b/ProcessList.c
@@ -357,7 +357,10 @@ void ProcessList_expandTree(ProcessList* this) {
    }
 }
 
+// Called on collapse-all toggle and on startup, possibly in non-tree mode
 void ProcessList_collapseAllBranches(ProcessList* this) {
+   ProcessList_buildTree(this); // Update `tree_depth` fields of the processes
+   this->needsSort = true; // ProcessList is sorted by parent now, force new sort
    int size = Vector_size(this->processes);
    for (int i = 0; i < size; i++) {
       Process* process = (Process*) Vector_get(this->processes, i);