As the developer of FolderGlance, I often get support mails regarding strange Finder behaviour. Sometimes, the root cause turns out to be FolderGlance, while other times something else or the Finder itself is to blame. The latter was the case for a bug I discovered in the Finder yesterday, which I've now reported to Apple (rdar://5657501). The bug manifests itself when you try to rename a file in the Finder's list view. Here are the steps required to reproduce the issue:

1. Open a new Finder window.
2. Set the view to List mode (Command-2)
3. Select a folder visible in the window, and expand it.
4. Select a file in the expanded folder.
5. Begin renaming the file by pressing the Return or Enter key.
6. Press the right arrow key to move the insertion point to the end of the file name.
7. Press and hold the shift key.
8. While holding the shift key, press and hold the left arrow key, as if to select a number of characters from the end of the filename towards the beginning. Note: It is important that the shift- and arrow keys are held continuously, and not released in between character selections.

The expected behaviour here is of course to have the characters from the filename selected, but instead what actually happens is that the sub-folder you try to rename the file in collapses, forcing you to start over.