Version:            (using KDE KDE 3.2.2)
Installed from:    Gentoo Packages

To see this in action try this:

1. Right-click desktop -> Create New -> Device -> Hard Disk Device
2. Change device to something you're allowed to mount/unmount (e.g. /mnt/usbdrive)
3. Click OK
4. Connect the device and click the new device icon.
5. Browse the files in Konqueror but don't open any.
6. Close the Konqueror window.
7. Right-click the icon and select Unmount.

This results in an error:

Could not umount device

umount: /mnt/usbdrive: device is busy
umount: /mnt/usbdrive: device is busy

KDE obviously can't control other processes, but it would be a huge usability improvement if closing a Konqueror window caused KDE to:

1. Check it's not using that device (e.g. a file copy operation, probably shown in a progress bar somewhere)
2. If it's not in use, close all file handles that arose from the browsing process

As a bonus it should try to be a bit more user friendly in cases where it's not directly responsible:

3. If the user has launched a file in some external app (e.g. mplayer) then it would be nice to say something more user friendly than the umount error like 'Please close any applications/files from the device'.

4. If possible, it could offer the user to 'list processes using this device'.

5. If the other processes are participating KDE apps it could be more specific and ask stuff like "Kaffeine is using a file from 'USB Drive'. Click 'Close file' if you still want to unmount it."  with options "Close file" / "Cancel".

Well some of this is being a bit hopeful but getting Konqueror to lay off all files after I close it would solve 90% of problems. ;-)