Add option to disable transforming multiple cels when we have only layers/frames selected on the Timeline

data/pref.xml

@@ -247,6 +247,7 @@
       <option id="modify_selection_brush" type="BrushType" default="BrushType::CIRCLE" />
       <option id="doubleclick_select_tile" type="bool" default="true" />
       <option id="force_rotsprite" type="bool" default="false" />
+      <option id="multicel_when_layers_or_frames" type="bool" default="true" />
     </section>
     <section id="quantization">
       <option id="with_alpha" type="bool" default="true" />

data/strings/en.ini

@@ -1055,6 +1055,14 @@ the selection when the mouse is inside it.
 END
 select_tile_with_double_click = Select a grid tile with double-click
 force_rotsprite = Force RotSprite even for right/straight angles
+multicel_when_layers_or_frames = Transform cels in selected layers or frames on timeline
+multicel_when_layers_or_frames_tooltip = <<<END
+When you transform the selection, all selected cels in the timeline
+will be transformed. With this option if you select multiple layers or
+frames, the transformation will be applied to all cels of the selected
+layers/frames. Without this option, multiple cels will be transformed
+only if you select multiple cels explicitly in the timeline.
+END
 autotimeline = Show timeline automatically
 autotimeline_tooltip = <<<END
 Show the timeline automatically

data/widgets/options.xml

@@ -224,6 +224,9 @@
 		 pref="selection.doubleclick_select_tile" />
           <check text="@.force_rotsprite" id="force_rotsprite"
 		 pref="selection.force_rotsprite"/>
+          <check text="@.multicel_when_layers_or_frames" id="multicel_when_layers_or_frames"
+		 tooltip="@.multicel_when_layers_or_frames_tooltip"
+		 pref="selection.multicel_when_layers_or_frames"/>
         </vbox>
 
         <!-- Timeline -->

src/app/ui/editor/pixels_movement.cpp

@@ -172,6 +172,14 @@ PixelsMovement::PixelsMovement(
   }
 }
 
+bool PixelsMovement::editMultipleCels() const
+{
+  return
+    (m_site.range().enabled() &&
+     (Preferences::instance().selection.multicelWhenLayersOrFrames() ||
+      m_site.range().type() == DocRange::kCels));
+}
+
 void PixelsMovement::setFastMode(const bool fastMode)
 {
   bool redraw = (m_fastMode && !fastMode);
@@ -977,7 +985,7 @@ CelList PixelsMovement::getEditableCels()
 {
   CelList cels;
 
-  if (m_site.range().enabled()) {
+  if (editMultipleCels()) {
     cels = get_unlocked_unique_cels(
       m_site.sprite(), m_site.range());
   }
@@ -1004,7 +1012,7 @@ CelList PixelsMovement::getEditableCels()
 
 bool PixelsMovement::gotoFrame(const doc::frame_t deltaFrame)
 {
-  if (m_site.range().enabled()) {
+  if (editMultipleCels()) {
     Layer* layer = m_site.layer();
     ASSERT(layer);
 

src/app/ui/editor/pixels_movement.h

@@ -120,6 +120,7 @@ namespace app {
     const Transformation& getTransformation() const { return m_currentData; }
 
   private:
+    bool editMultipleCels() const;
     void stampImage(bool finalStamp);
     void stampExtraCelImage();
     void onPivotChange();