fix crash when directory is changed

source/quam/archive.cc

@@ -98,9 +98,9 @@ namespace Arc {
 			return Qt::NoItemFlags;
 		} else {
 			return Qt::ItemIsSelectable  |
-			        Qt::ItemIsDragEnabled |
-			        Qt::ItemIsEnabled     |
-			        Qt::ItemNeverHasChildren;
+			       Qt::ItemIsDragEnabled |
+			       Qt::ItemIsEnabled     |
+			       Qt::ItemNeverHasChildren;
 		}
 	}
 
@@ -145,6 +145,12 @@ namespace Arc {
 
 	void Model::setDir(Dir *dir) {
 		if(dir != m_dir) {
+			emit layoutAboutToBeChanged();
+			for(int row = 0, rows = rowCount(); row < rows; row++) {
+				for(int col = 0, cols = columnCount(); col < cols; col++) {
+					changePersistentIndex(index(row, col), QModelIndex{});
+				}
+			}
 			m_dir = dir;
 			emit layoutChanged();
 			emit dirChanged(dir);