diff --git a/melib/src/structs.rs b/melib/src/structs.rs
index a3d93dc5c..a52a417e3 100644
--- a/melib/src/structs.rs
+++ b/melib/src/structs.rs
@@ -38,7 +38,7 @@ impl<T: Default + Copy + std::fmt::Debug> StackVec<T> {
         if self.len == 0 {
             return None;
         }
-        if self.len >= self.array.len() {
+        if self.len > self.array.len() {
             self.len -= 1;
             self.heap_vec.pop()
         } else {
@@ -60,7 +60,7 @@ impl<T: Default + Copy + std::fmt::Debug> StackVec<T> {
         }
     }
     pub fn remove(&mut self, i: usize) -> T {
-        if self.len >= self.array.len() {
+        if self.len > self.array.len() {
             self.heap_vec.remove(i)
         } else {
             let ret = std::mem::replace(&mut self.array[i], T::default());
@@ -71,6 +71,18 @@ impl<T: Default + Copy + std::fmt::Debug> StackVec<T> {
             ret
         }
     }
+
+    pub fn set(&mut self, i: usize, val: T) {
+        debug_assert!(i < self.len);
+        if self.len > self.array.len() {
+            self.heap_vec[i] = val;
+            if i + 1 < self.array.len() {
+                self.array[i] = val;
+            }
+        } else {
+            self.array[i] = val;
+        }
+    }
 }
 
 pub struct StackVecIter<'a, T: Default + Copy + std::fmt::Debug> {
@@ -108,7 +120,7 @@ impl<T: Default + Copy + std::fmt::Debug> Index<usize> for StackVec<T> {
     type Output = T;
 
     fn index(&self, idx: usize) -> &T {
-        if self.len >= self.array.len() {
+        if self.len > self.array.len() {
             &self.heap_vec[idx]
         } else {
             &self.array[idx]