timeline: fix bug in trackviewitem drag/drop

app/widget/timelinewidget/tool/import.cpp

@@ -87,8 +87,14 @@ void ImportTool::DragEnter(TimelineViewMouseEvent *event)
       }
     }
 
-    PrepGhosts(drag_start_.GetFrame() - parent()->SceneToTime(import_pre_buffer_),
-               drag_start_.GetTrack().index());
+    // Create a reasonable amount of space to inset the cursor by when importing
+    ghost_offset_ = drag_start_.GetFrame();
+
+    if (!event->GetBypassImportBuffer()) {
+      ghost_offset_ -= parent()->SceneToTime(import_pre_buffer_);
+    }
+
+    PrepGhosts(ghost_offset_, drag_start_.GetTrack().index());
 
     if (parent()->HasGhosts() || !parent()->GetConnectedNode()) {
       event->accept();
@@ -107,6 +113,12 @@ void ImportTool::DragMove(TimelineViewMouseEvent *event)
 
     if (parent()->HasGhosts()) {
       rational time_movement = event->GetFrame() - drag_start_.GetFrame();
+
+      // Keep ghost offset no lower than 0
+      if (ghost_offset_ + time_movement < 0) {
+        time_movement = -ghost_offset_;
+      }
+
       int track_movement = event->GetTrack().index() - drag_start_.GetTrack().index();
 
       time_movement = ValidateTimeMovement(time_movement);

app/widget/timelinewidget/tool/import.h

@@ -60,6 +60,8 @@ private:
 
   int import_pre_buffer_;
 
+  rational ghost_offset_;
+
 };
 
 }

app/widget/timelinewidget/trackview/trackviewitem.cpp

@@ -87,6 +87,7 @@ void TrackViewItem::dragEnterEvent(QDragEnterEvent *event)
   TimelineViewMouseEvent e(0, 1, 1, track_->ToReference(), Qt::NoButton, event->keyboardModifiers());
   e.SetMimeData(event->mimeData());
   e.SetEvent(event);
+  e.SetBypassImportBuffer(true);
   emit DragEntered(&e);
 }
 

app/widget/timelinewidget/view/timelineviewmouseevent.h

@@ -47,7 +47,8 @@ public:
     button_(button),
     modifiers_(modifiers),
     source_event_(nullptr),
-    mime_data_(nullptr)
+    mime_data_(nullptr),
+    bypass_import_buffer_(false)
   {
   }
 
@@ -117,6 +118,9 @@ public:
       source_event_->ignore();
   }
 
+  bool GetBypassImportBuffer() const { return bypass_import_buffer_; }
+  void SetBypassImportBuffer(bool e) { bypass_import_buffer_ = e; }
+
 private:
   qreal scene_x_;
   double scale_x_;
@@ -132,6 +136,8 @@ private:
 
   const QMimeData* mime_data_;
 
+  bool bypass_import_buffer_;
+
 };
 
 }