When a folder plasmoid is added to the panel it creates a button that opens the panel when clicked. That panel is not sizeable (or I found no way to do it). At the same desktop I have another file plasmoid put directly in the desktop that has handlers and have no problem being resized through them.

Reproducible: Always

Steps to Reproduce:
1. Install kubuntu 15.04
2. Add a folder plasmoid to the desktop and another to the default panel.
3. Try to resize the second (handlers do not appear, no combination of keys I am aware of let you resize the plasmoid)

Actual Results:  
Handlers do not appear, no combination of keys I am aware of let you resize the plasmoid. Editing the panel don't seem to let you edit the size of the Folder Plasmoid, only the position of the button that shows it.

Expected Results:  
There should be a way to accommodate the size of the folder to the desired one (only the size, not the position as that one comes in relation to the actual position of the button in the panel).

If that is not possible by design it would be nice to know what rc file holds actual size and what is the logic of the data in that file, so we can change it by hand.
The problem applies to all other applets, such as the launcher.