@@ -1344,2 +1344,4 @@
 }
 
+void GreasePencil::add_duplicate_drawings(
+    const int add_num, const blender::bke::greasepencil::Drawing &duplicated_drawing)

@@ -1359,2 +1373,4 @@
 }
 
+bool GreasePencil::insert_duplicate_frame(blender::bke::greasepencil::Layer &layer,
+                                          const GreasePencilFrame &duplicated_frame,

@@ -1361,0 +1381,4 @@
+
+  const int drawing_index = do_instance ? duplicated_frame.drawing_index :
+                                          int(this->drawings().size());
+  const int duration = 0;

@@ -1361,0 +1390,4 @@
+
+  frame->type = duplicated_frame.type;
+
+  const GreasePencilDrawingBase *drawing_base = this->drawings()[duplicated_frame.drawing_index];

@@ -1361,0 +1391,4 @@
+  frame->type = duplicated_frame.type;
+
+  const GreasePencilDrawingBase *drawing_base = this->drawings()[duplicated_frame.drawing_index];
+  BLI_assert_msg((drawing_base->type == GP_DRAWING),

@@ -768,0 +777,4 @@
+  using namespace blender::bke::greasepencil;
+  Layer *layer = static_cast<Layer *>(ale->data);
+  GreasePencil *grease_pencil = reinterpret_cast<GreasePencil *>(ale->id);
+  const int frame_number = ac->scene->r.cfra;

@@ -768,0 +780,4 @@
+  const int frame_number = ac->scene->r.cfra;
+
+  if (layer->frames().contains(frame_number)) {
+    /* A frame already exists at the current frame number. */

@@ -768,0 +788,4 @@
+  if (hold_previous) {
+    const GreasePencilFrame *active_frame = layer->frame_at(frame_number);
+    if ((active_frame == nullptr) || (active_frame->is_null())) {
+      /* There is no active frame to hold to, or it's a null frame. */

@@ -768,0 +805,4 @@
+  }
+
+  if (changed) {
+    layer->tag_frames_map_keys_changed();

@@ -1406,0 +1436,4 @@
+                                          const int duplicate_frame_number,
+                                          const bool do_instance)
+{
+  using namespace blender;

@@ -1406,0 +1438,4 @@
+{
+  using namespace blender;
+
+  BLI_assert(layer.frames().contains(frame_number));

@@ -1406,0 +1454,4 @@
+  const GreasePencilDrawingBase *drawing_base = this->drawings(frame.drawing_index);
+  switch (drawing_base->type) {
+    case GP_DRAWING: {
+      const GreasePencilDrawing *drawing = reinterpret_cast<const GreasePencilDrawing *>(

@@ -1406,0 +1457,4 @@
+      const GreasePencilDrawing *drawing = reinterpret_cast<const GreasePencilDrawing *>(
+          drawing_base);
+      if (do_instance) {
+        /* TODO : add user to the drawing. */

@@ -1406,0 +1460,4 @@
+        /* TODO : add user to the drawing. */
+      }
+      else {
+        this->add_duplicate_drawings(1, drawing->wrap());

@@ -34,6 +37,8 @@
 #include "BKE_fcurve.h"
 #include "BKE_global.h"
 #include "BKE_gpencil_legacy.h"
+#include "BKE_grease_pencil.h"

@@ -481,10 +481,17 @@ typedef struct GreasePencil {
   void remove_layer(blender::bke::greasepencil::Layer &layer);
 
   void add_empty_drawings(int add_num);
+  void add_duplicate_drawings(int add_num,