Bug 312959 [Import/Export] importing file from big disk hangs UI
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/wizards/datatransfer/WizardFileSystemResourceImportPage1.java
File sourceDirectory = getSourceDirectory();
        if (sourceDirectory == null) {
			return null;
		}
        return selectFiles(sourceDirectory,
        		fileSystemStructureProvider);
    }
    /**
     * Returns a content provider for <code>FileSystemElement</code>s that returns
     * only folders as children.
     */
    protected ITreeContentProvider getFolderProvider() {
        return new WorkbenchContentProvider() {
            public Object[] getChildren(Object o) {
                if (o instanceof MinimizedFileSystemElement) {
                    MinimizedFileSystemElement element = (MinimizedFileSystemElement) o;
                    return element.getFolders(
                    		fileSystemStructureProvider).getChildren(
                            element);
                }
                return new Object[0];
            }
            public boolean hasChildren(Object o) {
                if (o instanceof MinimizedFileSystemElement) {
                    MinimizedFileSystemElement element = (MinimizedFileSystemElement) o;
                    if (element.isPopulated()) {
						return getChildren(element).length > 0;
					}
                    
                    return true;