projectexplorer: added functionality for opening a folder in another tab/window

app/window/mainwindow/mainwindow.cpp

@@ -176,6 +176,33 @@ void MainWindow::SetTaskbarButtonProgress(int value, int max)
 }
 #endif
 
+void MainWindow::FolderOpen(Project *p, Item *i, bool floating)
+{
+  ProjectPanel* panel = PanelManager::instance()->CreatePanel<ProjectPanel>(this);
+
+  panel->set_project(p);
+  panel->set_root(i);
+
+  // Tabify with source project panel
+  foreach (ProjectPanel* proj_panel, project_panels_) {
+    if (proj_panel->project() == p) {
+      tabifyDockWidget(proj_panel, panel);
+      break;
+    }
+  }
+
+  panel->setFloating(floating);
+
+  panel->show();
+  panel->raise();
+
+  // If the panel is closed, just destroy it
+  panel->SetSignalInsteadOfClose(true);
+  connect(panel, &ProjectPanel::CloseRequested, this, &MainWindow::FolderCloseRequested);
+
+  folder_panels_.append(panel);
+}
+
 void MainWindow::SetFullscreen(bool fullscreen)
 {
   if (fullscreen) {
@@ -251,6 +278,12 @@ void MainWindow::ProjectClose(Project *p)
     }
   }
 
+  foreach (ProjectPanel* panel, folder_panels_) {
+    if (panel->project() == p) {
+      panel->close();
+    }
+  }
+
   // Close any open sequences from project
   QList<ItemPtr> open_sequences = p->get_items_of_type(Item::kSequence);
 
@@ -326,6 +359,14 @@ void MainWindow::ProjectCloseRequested()
   Core::instance()->CloseProject(p, true);
 }
 
+void MainWindow::FolderCloseRequested()
+{
+  ProjectPanel* panel = static_cast<ProjectPanel*>(sender());
+
+  folder_panels_.removeOne(panel);
+  panel->deleteLater();
+}
+
 TimelinePanel* MainWindow::AppendTimelinePanel()
 {
   TimelinePanel* panel = AppendPanelInternal<TimelinePanel>(timeline_panels_);