Platform: Windows XP

Reproduce:

1.) Create a QFileSystemModel:

QFileSystemModel *fileSystemModel = new QFileSystemModel;
fileSystemModel->setRootPath(QDir::currentPath());

2.) Set a filter to this model to display only directories:

fileSystemModel->setFilter(QDir::AllDirs | QDir::NoDotAndDotDot);

3.) Create a QTreeView to render the model:

QTreeView *fileTree = new QTreeView;
fileTree->setModel(fileSystemModel);

4.) Hide the header and set columns 1-3 invisible. So you get a directory tree structure.

Problem: Some tree nodes without children (i. e. directories without including subdirectories) are rendered as expandable, i. e. a "+" is rendered left to them. If you click the node, it is rendered as collapsable. If you expand another node, the tree probably is updated and the node is correctly rendered as a leave.