> Digicam and dcraw are already part of the normal TP10 install. Separate download and install isn't needed.
I didn't mean to suggest that. The release notes explain how to assign one of the raw plug-ins to your raw filetypes so they can be thumbnailed, which you said you were having problems with. But it turns out they were just not being shown.
Note that when you tick file types in the File Types dialog, it only adds them to what is called 'selected filetypes', which is what is shown by default in the thumbnail listing. However, you can quickly override that using the funnel button (above the listing) if you want to see all files or just files of one type, e.g. *.CR2. You can also specify a filter in the pulldown box to its right, for instance ".jpg;.tif;.png".