As the universal expression goes, you "drag and drop" the item (whatever), FROM whereever it was (click and hold item), TO whereever it's to go (here, the Pianoteq window), THEN release the hold (drop item).

If the drag is with the left mouse-button this "moves" the item from the click-point to the release-point (if the move is only within the same hard drive and is in a Windows system - Mac may be different, ask an owner).

If the right mouse-button is used for the drag (or the left is, but the drag's from one drive to another), drag-and-drop results only in a dragged copy of the item being dropped, the original staying put.

It's extremely unusual to find  anyone needing this extremely usual action explained, but I'll play along!

Anyway, the result with Pianoteq drag-and-drop is the dropped item disappears from view, because it has been tucked away where Modartt wants it put (not necessarily in the Modartt folder, for these particular items a couple of pointers to where is at the Folders heading, under the General tab of the Options window).

ADDED: Hm, just noticed the "Add-on" of your thread's title, and if you mean that literally it means the answer above doesn't fit, for 'Add Ons' are wired into the program, you purchase them and thereby get a licence code, which is to be entered on the same page as you register the main progam. More detail you can find at that entry point, but not a lot, it adds up to 'wait a bit while we OK your installation'.

To stress what's the difference here to the drag-and-drop above (which Pianoteq uses plenty), NO need to download or put copies of anything anywhere, for purchasable Add Ons. Only the licence is needed.

Free Add Ons (which you do download) you handle with drag and drop as above. They're two, Bells and Historic Instruments - (the temptation to type Whistles is awful).

Thank you for your detailed explaination. DP

If the drag is with the left mouse-button this "moves" the item from the click-point to the release-point (if the move is only within the same hard drive and is in a Windows system - Mac may be different, ask an owner).

If the right mouse-button is used for the drag (or the left is, but the drag's from one drive to another), drag-and-drop results only in a dragged copy of the item being dropped, the original staying put.

It's extremely unusual to find  anyone needing this extremely usual action explained, but I'll play along!

Anyway, the result with Pianoteq drag-and-drop is the dropped item disappears from view, because it has been tucked away where Modartt wants it put (not necessarily in the Modartt folder, for these particular items a couple of pointers to where is at the Folders heading, under the General tab of the Options window).

ADDED: Hm, just noticed the "Add-on" of your thread's title, and if you mean that literally it means the answer above doesn't fit, for 'Add Ons' are wired into the program, you purchase them and thereby get a licence code, which is to be entered on the same page as you register the main progam. More detail you can find at that entry point, but not a lot, it adds up to 'wait a bit while we OK your installation'.

To stress what's the difference here to the drag-and-drop above (which Pianoteq uses plenty), NO need to download or put copies of anything anywhere, for purchasable Add Ons. Only the licence is needed.

Free Add Ons (which you do download) you handle with drag and drop as above. They're two, Bells and Historic Instruments - (the temptation to type Whistles is awful).

I downloaded two free pianos and how do I get them to appear on my instrument list? How do I perform this procedure of  "dropping each downloaded .ptq file onto the Pianoteq interface."? I already transfered them into the Moddart folder altready. Thanks DP