Two songs appear in list when I add one

[Roy Dennis]

Which version of Hoster are you using ?
Which version of Windows ?

Do you use a mouse or the computer track pad when this happens ?

Does it do the same thing if you use the Add button or drag & drop it instead of the double click feature ?

If it only happens using the mouse or touch pad I should check out your settings for those. Open your control panel and look for Mouse then try adjusting the double click speed option see if that helps. If you use the touch pad then select the tab for touch pad then options for that and run through all the options for that. I personally turn of all the two finger & three finger options but just thinking you might find something in those settings that will stop it happening.
If you use a mouse check out all the settings available for that or even try a different mouse see if the problem still occurs.